Pierre-Louis Maupertuis
(1698–1759)
Source: Wikipedia
Pierre Louis Moreau de Maupertuis was a French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Prussian Academy of Science, at the invitation of Frederick the Great. His work in natural history is interesting in relation to modern science, since he touched on aspects of heredity and the struggle for life. Some historians of science point to his work in biology as a significant precursor to the development of evolutionary theory, specifically the theory of natural selection. Other writers contend that his remarks are cursory, vague, or incidental to that particular argument. Mayr's verdict was "He was neither an evolutionist, nor one of the founders of the theory of natural selection [but] he was one of the pioneers of genetics". Maupertuis espoused a theory of pangenesis, postulating particles from both mother and father as responsible for the characters of the child. Bowler credits him with studies on heredity, with the natural origin of human races, and with the idea that forms of life may have changed with time.
Joseph Gottlieb Kölreuter
(1733–1806)
Source: Wikipedia
Joseph Gottlieb Kölreuter, also spelled Koelreuter or Kohlreuter, was a German botanist who pioneered the study of plant fertilization, hybridization and was the first to detect self-incompatibility. He was an observer as well as a rigorous experimenter who used careful crossing experiments although he did not inquire into the nature of heritability. Kölreuter was the oldest of three sons of an apothecary in Karlsruhe, Germany, and grew up in Sulz. He took an early interest in natural history and made a collection of local insects. At the age of fifteen he went to study medicine at the University of Tübingen under physician and botanist Johann Georg Gmelin who had returned from St. Petersburg. Gmelin had an interest in floral biology and he reprinted a work by Rudolf Jakob Camerarius (who also taught at Tübingen) who was the first to demonstrate sexual reproduction in plants. In his inaugural address in 1749 Gmelin talked the need for research on the origin of new species by hybridization. Kölreuter major works were produced as four reports Vorlaufige Nachricht von einigen das Geschlecht der Pflanzen betreffenden Versuchen und Beobachtungen (1761), Fortsetzung (1763), Zweyte Fortsetzung (1764), and Dritte Fortsetzung (1766). In all he conducted nearly 500 different hybridization experiments across 138 species and examined the pollen characteristics of over a 1000 plant species.
Ernst Mayr. 1986. Joseph Gottlieb Kölreuter's Contributions to Biology. Osiris, 2:135-176.
Thomas Robert Malthus
(1766–1834)
Source: Wikipedia
Thomas Robert Malthus was an English cleric and scholar, influential in the fields of political economy and demography. Malthus himself used only his middle name, Robert. In his book An Essay on the Principle of Population, Malthus observed that an increase in a nation's food production improved the well-being of the populace, but the improvement was temporary because it led to population growth, which in turn restored the original per capita production level. In other words, mankind had a propensity to utilize abundance for population growth rather than for maintaining a high standard of living, a view that has become known as the "Malthusian trap" or the "Malthusian spectre". Populations had a tendency to grow until the lower class suffered hardship and want and greater susceptibility to famine and disease, a view that is sometimes referred to as a Malthusian catastrophe. Malthus wrote in opposition to the popular view in 18th-century Europe that saw society as improving and in principle as perfectible. He saw population growth as being inevitable whenever conditions improved, thereby precluding real progress towards a utopian society: "The power of population is indefinitely greater than the power in the earth to produce subsistence for man". His views became influential, and controversial, across economic, political, social and scientific thought. Pioneers of evolutionary biology read him, notably Charles Darwin and Alfred Russel Wallace.
Theodor Schwann
(1810–1882)
Source: Wikipedia
Theodor Schwann was a German physiologist. His many contributions to biology include the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the organic nature of yeast, and the invention of the term metabolism. In 1837, Matthias Jakob Schleiden viewed and stated that new plant cells formed from the nuclei of old plant cells. While dining that year with Schwann, the conversation turned on the nuclei of plant and animal cells. Schwann remembered seeing similar structures in the cells of the notochord (as had been shown by Müller) and instantly realized the importance of connecting the two phenomena. The resemblance was confirmed without delay by both observers, and the results soon appeared in Schwann's famous Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants, in which he declared that "All living things are composed of cells and cell products". This became cell theory or cell doctrine. In the course of his verification of cell theory, Schwann proved the cellular origin and development of the most highly differentiated tissues including nails, feathers, and tooth enamel. Schwann established a basic principle of embryology by observing that the ovum is a single cell that eventually develops into a complete organism.
Matthias Jakob Schleiden
(1804–1881)
Source: Wikipedia
Matthias Jakob Schleiden was a German botanist and co-founder of cell theory, along with Theodor Schwann and Rudolf Virchow. Born in Hamburg, Schleiden was educated at University of Jena, then practiced law in Heidelberg, but soon developed his love for botany into a full-time pursuit. Schleiden preferred to study plant structure under the microscope. While a professor of botany at the University of Jena, he wrote Contributions to our knowledge of phytogenesis (1838), in which he stated that all parts of the plant organism are composed of cells. Thus, Schleiden and Schwann became the first to formulate what was then an informal belief as a principle of biology equal in importance to the atomic theory of chemistry. He also recognized the importance of the cell nucleus, discovered in 1831 by the Scottish botanist Robert Brown, and sensed its connection with cell division. Schleiden was one of the first German biologists to accept Charles Darwin's theory of evolution. He became professor of botany at the University of Dorpat in 1863. He concluded that all plant parts are made of cells and that an embryonic plant organism arises from the one cell.
Rudolf Virchow
(1821–1902)
Source: Wikipedia
Rudolf Ludwig Carl Virchow was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician, known for his advancement of public health. He is known as "the father of modern pathology" because his work helped to discredit humourism, bringing more science to medicine. He is also known as the founder of social medicine and veterinary pathology, and to his colleagues, the "Pope of medicine". A prolific writer, his scientific writings alone exceeded 2,000 in number. Among his books, Cellular Pathology published in 1858 is regarded as the root of modern pathology. This work also popularised the third dictum in cell theory: Omnis cellula e cellula ("All cells come from cells"); although his idea originated in 1855. Virchow is credited with several very important discoveries. His most widely known scientific contribution is his cell theory, which built on the work of Theodor Schwann. He was one of the first to accept the work of Robert Remak, who showed the origins of cells was the division of pre-existing cells. He did not initially accept the evidence for cell division, believing it only occurs in certain types of cells. When it dawned on him that Remak might be right, in 1855, he published Remak's work as his own, which caused a falling out between the two. This work, Virchow encapsulated in the epigram Omnis cellula e cellula ("all cells (come) from cells"), which he published in 1855. He was an ardent anti-evolutionist. He referred to Charles Darwin as an "ignoramus" and his own student Ernst Haeckel, the leading advocate of Darwinism in Germany, as a "fool". He discredited the original specimen of Neanderthal man as nothing but that of a deformed human, and not an ancestral species.
Charles Darwin
(1809–1882)
Source: Wikipedia
Charles Robert Darwin was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. He established that all species of life have descended over time from common ancestors and, in a joint publication with Alfred Russel Wallace, introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s, the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.
Darwin Online: The world's largest and most widely used resource on Darwin, containing his complete publications, his private papers and manuscripts, and much supplementary material.
Alfred Russel Wallace
(1823–1913)
Source: Wikipedia
Alfred Russel Wallace was a British naturalist, explorer, geographer, anthropologist, and biologist. He is best known for independently conceiving the theory of evolution through natural selection; his paper on the subject was jointly published with some of Charles Darwin's writings in 1858. This prompted Darwin to publish his own ideas in On the Origin of Species. Wallace did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the animals are largely of Asian origin, and an eastern portion where the fauna reflect Australasia. He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography". Wallace was one of the leading evolutionary thinkers of the 19th century and made many other contributions to the development of evolutionary theory besides being co-discoverer of natural selection. These included the concept of warning colouration in animals, and the Wallace effect, a hypothesis on how natural selection could contribute to speciation by encouraging the development of barriers against hybridisation. Wallace was strongly attracted to unconventional ideas (such as evolution). His advocacy of spiritualism and his belief in a non-material origin for the higher mental faculties of humans strained his relationship with some members of the scientific establishment.
The Alfred Russel Wallace Website
Encyclopædia Britannica: Alfred Russel Wallace
The Alfred Russel Wallace Page
The New Yorker: Missing Link, Alfred Russel Wallace, Charles Darwin’s neglected double.
NOVA: Great Minds Think Alike, How Alfred Wallace Came to Share Darwin's Revolutionary Insight
Wallace Online (the first complete edition of the writings of Alfred Russel Wallace, including the first compilation of his specimens)
Alfred Russel Wallace, Darwin Correspondence Project
Carl Nägeli
(1817–1891)
Source: Wikipedia
Carl Wilhelm von Nägeli was a Swiss botanist. He studied cell division and pollination but became known as the man who discouraged Gregor Mendel from further work on genetics. He rejected natural selection as a mechanism of evolution, favouring orthogenesis driven by a supposed "inner perfecting principle". The writer Simon Mawer, in his book Gregor Mendel: Planting the Seeds of Genetics (2006), gives us an interesting and detailed account of Nägeli's correspondence with Mendel. Mawer underlines that, at the time Nägeli was writing to the friar from Moravia, Nägeli "must have been preparing his great work entitled A mechanico-physiological theory of organic evolution (published in 1884, the year of Mendel's death) in which he proposes the concept of the 'idioplasm' as the hypothetical transmitter of inherited characters". Mawer notes that, in this Nägeli book, there is not a single mention of the work of Gregor Mendel. That prompted him to write: "We can forgive von Nägeli for being obtuse and supercilious. We can forgive him for being ignorant, a scientist of his time who did not really have the equipment to understand the significance of what Mendel had done despite the fact that he (von Nägeli) speculated extensively about inheritance. But omitting an account of Mendel's work from his book is, perhaps, unforgivable." (Mawer 2006, p. 81)
Francis Galton
(1822–1911)
Source: Wikipedia
Sir Francis Galton was an English Victorian statistician, progressive, polymath, sociologist, psychologist, anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, and psychometrician. He was knighted in 1909. Galton produced over 340 papers and books. He also created the statistical concept of correlation and widely promoted regression toward the mean. He was the first to apply statistical methods to the study of human differences and inheritance of intelligence, and introduced the use of questionnaires and surveys for collecting data on human communities, which he needed for genealogical and biographical works and for his anthropometric studies.
GALTON.ORG — An extensive on-line collection, providing a biography, Galton's collected works, and more.
The Francis Galton Papers: A collection of digitized resources maintained by the Wellcome Library (part of the Wellcome Trust)
Friedrich Miescher
(1844–1895)
Source: Wikipedia
Johannes Friedrich Miescher was a Swiss physician and biologist. He was the first researcher to isolate nucleic acid. Miescher isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in 1869 in Felix Hoppe-Seyler's laboratory at the University of Tübingen, Germany, paving the way for the identification of DNA as the carrier of inheritance. The significance of the discovery, first published in 1871, was not at first apparent, and it was Albrecht Kossel who made the initial inquiries into its chemical structure. Later, Friedrich Miescher raised the idea that the nucleic acids could be involved in heredity.
Ralf Dahm. 2008. Discovering DNA: Friedrich Miescher and the early years of nucleic acid research. Human Genetics, 122:565. doi:10.1007/s00439-007-0433-0
William Keith Brooks
(1848–1908)
Source: Wikipedia
William Keith Brooks received a Bachelor of Arts degree from Williams College in 1870 and a PhD from Harvard in 1875. With the opening of The Johns Hopkins University in 1876, Brooks received one of the university's initial fellowships and he quickly advanced within the organization, ultimately serving as Professor of Zoology and Head of the Biological Department. At the young age of 36 he was elected a member of the National Academy. He was chosen as a member of the American Philosophical Society in 1886 and of the Academy of Natural Science in 1887. Although many of Brooks' scientific contributions represent solid, nineteeth-century work, his most lasting effect came from his long-standing conviction that the processes of heredity were themselves a proper subject of investigation. In 1876 he wrote a paper entitled "A Provisional Hypothesis of Pangenesis" and he gave the subject a book-length treatment in his The Law of Heredity. A Study of the Cause of Variation and the Origin of Living Organisms. He was known as both a man of deep, abstract thought and an excellent teacher, as evidenced by the fact that many of the still well-known pioneers of genetics had, at one time or another, studied with him: viz. Thomas Morgan, E. B. Wilson, and William Bateson.
Eduard Strasburger
(1844–1912)
Source: Wikipedia
Eduard Adolf Strasburger was a Polish-German professor who was one of the most famous botanists of the 19th century. Strasburger studied biological sciences in Paris, Bonn and Jena, receiving a PhD in 1866 after working with Nathanael Pringsheim. In 1868 he taught at the University of Warsaw. In 1869 he was appointed professor of botany at the University of Jena. Since 1881 he was head of the Botanisches Institut at the University of Bonn. Together with Walther Flemming, and Edouard van Beneden he elucidated chromosome distribution during cell division.
Walther Flemming
(1843–1905)
Source: Wikipedia
Walther Flemming was a German biologist and a founder of cytogenetics. Flemming trained in medicine at University of Rostock, graduating in 1868. Afterwards, he served in 1870–71 as a military physician in the Franco-Prussian War. From 1873 to 1876 he worked as a teacher at the University of Prague. In 1876 he accepted a post as a professor of anatomy at the University of Kiel. He became the director of the Anatomical Institute and stayed there until his death. With the use of aniline dyes he was able to find a structure which strongly absorbed basophilic dyes, which he named chromatin. He identified that chromatin was correlated to threadlike structures in the cell nucleus – the chromosomes (meaning coloured bodies), which were named thus later by German anatomist Wilhelm von Waldeyer-Hartz (1841–1923). The Belgian scientist Edouard Van Beneden (1846–1910) had also independently observed chromosomes. Flemming investigated the process of cell division and the distribution of chromosomes to the daughter nuclei, a process he called mitosis from the Greek word for thread. However, he did not see the splitting into identical halves, the daughter chromatids. He studied mitosis both in vivo and in stained preparations, using as the source of biological material the fins and gills of salamanders. These results were published first in 1878 and in 1882 in the seminal book Zellsubstanz, Kern und Zelltheilung (Cell substance, nucleus and cell division). On the basis of his discoveries, Flemming surmised for the first time that all cell nuclei came from another predecessor nucleus (he coined the phrase omnis nucleus e nucleo, after Virchow's omnis cellula e cellula).
Neidhard Paweletz. 2001. Walther Flemming: pioneer of mitosis research. Nature Reviews Molecular Cell Biology, 2:72-75. | doi:10.1038/35048077
Édouard Joseph Louis Marie van Beneden
(1846–1910)
Source: Wikipedia
Édouard Joseph Louis Marie Van Beneden was a Belgian embryologist, cytologist and marine biologist. He was professor of zoology at the University of Liège. He contributed to cytogenetics by his works on the roundworm Ascaris. In this work he discovered and described the process of meiosis — a two-cell-division process by which cells reduce the number of chromosomes in preparation for the production of gametes. Van Beneden also elucidated, together with Walther Flemming and Eduard Strasburger, the essential facts of mitosis — the single-cell-division process that distributes equal chromosome complements to each of the two daughter cells.
Heinrich Wilhelm Gottfried von Waldeyer-Hartz
(1836–1921)
Source: Wikipedia
Heinrich Wilhelm Gottfried von Waldeyer-Hartz was a German anatomist, famous for consolidating the neuron theory of organization of the nervous system and for naming the chromosome. He is also remembered in two macroanatomical structures of the human body which were named after him: Waldeyer's tonsillar ring (the lymphoid tissue ring of the naso- and oropharynx) and Waldeyer's glands (of the eyelids). Waldeyer also studied the basophilic stained filaments which had been found (by his colleague of Kiel, Walther Flemming) to be the main constituents of chromatin, the material inside the cell nucleus. Although the full significance of chromosomes for genetics and for cell biology was still to be discovered, these filaments were known to be involved in the phenomenon of cell division discovered by Flemming, named mitosis, as well as in meiosis. In 1888, Waldeyer coined the term chromosome — colored body — to describe them.
T. Cremer and C. Cremer. 1988. Centennial of Wilhelm Waldeyer’s introduction of the term “chromosome” in 1888. Cytogenetics and Cell Genetics, 48:66–67. (DOI:10.1159/000132591)
Waldeyer's 1888 paper in which he uses the word chromosome: Über Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen.
August Weismann
(1834–1914)
Source: Wikipedia
August Friedrich Leopold Weismann was a German evolutionary biologist. Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg. His main contribution involved his Germ Plasm Theory, at one time also known as Weismannism, according to which inheritance (in a multicellular organism) only takes place by means of the germ cells — the gametes such as egg cells and sperm cells. Other cells of the body — somatic cells — do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck. The idea of the Weismann barrier is central to the modern evolutionary synthesis, though scholars do not express it today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann became one of the first biologists to deny Lamarckism entirely. Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection. Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–1940, and "one of the great biologists of all time".
Essays Upon Heredity — a collection of Weismann's writing on hereditary issues.
Yawen Zou. 2015. The Germ-Plasm: a Theory of Heredity (1893), by August Weismann. The Embryo Project Encyclopedia.
Edwin G. Conklin. 1915. August Weismann. Proceedings of the American Philosophical Society, 54:3-12.
Edmund Beecher Wilson
(1856–1939)
Source: Wikipedia
Edmund Beecher Wilson was a pioneering American zoologist and geneticist. He wrote one of the most famous textbooks in the history of modern biology, The Cell in Development and Inheritance. He and Nettie Maria Stevens were the first researchers to describe the chromosomal basis of sex, but they conducted their research independently of each other. Wilson is credited as America's first cell biologist. In 1898 he used the similarity in embryos to describe phylogenetic relationships. By observing spiral cleavage in molluscs, flatworms and annelids he concluded that the same organs came from the same group of cells and concluded that all these organisms must have a common ancestor.
Erich von Tschermak
(1864–1933)
Source: Wikipedia
Erich Tschermak, Edler von Seysenegg was an Austrian agronomist who developed several new disease-resistant crops, including wheat-rye and oat hybrids. He was a son of the Moravia-born mineralogist Gustav Tschermak von Seysenegg. His maternal grandfather was the famous botanist, Eduard Fenzl, who taught Gregor Mendel botany during his student days in Vienna.
Hugo de Vries
(1848–1935)
Source: Wikipedia
Hugo Marie de Vries was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution. In 1889, De Vries published his book Intracellular Pangenesis, in which, based on a modified version of Charles Darwin's theory of Pangenesis of 1868, he postulated that different characters have different hereditary carriers. He specifically postulated that inheritance of specific traits in organisms comes in particles. He called these units pangenes, a term 20 years later to be shortened to genes by Wilhelm Johannsen.
Ralph E. Cleland. 1936. Hugo de Vries. Proceedings of the American Philosophical Society, 76:248-250.
William Bateson
(1861–1926)
Source: Wikipedia
William Bateson was an English biologist who was the first person to use the term genetics to describe the study of heredity, and the chief populariser of the ideas of Gregor Mendel following their rediscovery in 1900 by Hugo de Vries and Carl Correns. Bateson first suggested using the word "genetics" to describe the study of inheritance and the science of variation in a personal letter to Adam Sedgwick who had been Darwin's professor), dated 18 April 1905. Bateson first used the term "genetics" publicly at the Third International Conference on Plant Hybridization in London in 1906.
Carl Correns
(1864–1933)
Source: Wikipedia
Carl Erich Correns was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendel's earlier paper on that subject, which he achieved simultaneously but independently of the botanists Erich Tschermak von Seysenegg and Hugo de Vries, and the agronomist William Jasper Spillman. Carl Correns conducted much of the foundational work for the field of genetics at the turn of the 20th century. He rediscovered and independently verified the work of Mendel in a separate model organism. He also discovered cytoplasmic inheritance, an important extension of Mendel's theories, which demonstrated the existence of extra-chromosomal factors on phenotype. Most of Correns' work went unpublished however, and was destroyed in the Berlin bombings of 1945.
Theodor Boveri
(1862–1915)
Source: Embryo Project
Theodor Heinrich Boveri was a German biologist. He was notable for first hypothesising the cellular processes that cause cancer. Boveri's work with sea urchins showed that it was necessary to have all chromosomes present in order for proper embryonic development to take place. This discovery was an important part of the Boveri–Sutton chromosome theory, which identifies chromosomes as the carriers of genetic material. The theory correctly explains the mechanism underlying the laws of Mendelian inheritance by identifying chromosomes with the paired factors (particles) required by Mendel's laws. The chromosome theory of inheritance is credited to papers by Walter Sutton in 1902 and 1903, as well as to independent work by Theodor Boveri during roughly the same period. Boveri's thoughts are summarized in his book Ergebnisse über die Konstitution der chromatischen Substanz des Zellkerns (Results on the constitution of the chromatic substance of the cell nucleus), Jena: Verlag von Gustav Fischer, 1904. His other significant discovery was the centrosome (1888), which he described as the especial organ of cell division. Boveri also discovered the phenomenon of chromatin diminution during embryonic development of the nematode Parascaris.
Clarence Erwin McClung
(1870–1946)
Source: Wikipedia
Clarence Erwin (CE) McClung was an American zoologist of wide-ranging interests. Although born in California, he spent much of his early life in Kansas. He originally studied pharmacy at Kansas University, receiving the Ph.G. degree in 1892. He taught pharmacy at the University for a year, but then his interest shifted to more general biological questions and he reenrolled as a student. From Kansas University he received the A.B. degree in 1896, the A.M. in 1898, and the Ph.D. in 1902. CE McClung made important contributions to early genetics, but he was also a general zoologist and paleontologist who received all of his degrees from Kansas and then spent his early career on the faculty there, ultimately assuming the positions of chair of the zoology department, curator of vertebrate paleontology, and even acting dean of the medical school. Early in his career, he undertook an investigation of spermatogenesis in Ziphidium fasciatum, a long-horned grasshopper. In this material he recognized that an object thought by some to be a nucleolus was actually an unpaired chromosome. Although others had noticed that this object was distributed asymmetrically into some but not all spermatozoa, McClung was the first to see that this could provide a cytological mechanism of sex determination.
D. H. Wenrich. 1946. Clarence Erwin McClung 1870-1946 Science, 103:551-552. DOI: 10.1126/science.103.2679.551
David Henry Wenrich Papers: A collection largely developed to support the Dr. Wenrich's efforts to honor Dr. Clarence Erwin McClung.
Archibald Garrod
(1857–1938)
Source: Wikipedia
Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. He also discovered alkaptonuria, understanding its inheritance. He served as Regius Professor of Medicine at the University of Oxford from 1920 to 1927. Garrod is best known for his scientific study of inborn errors of metabolism. He developed an increasing interest in chemical pathology, and investigated urine chemistry as a reflection of systemic metabolism and disease. This research, combined with the new understanding of Mendelian inheritance, evolved from an investigation of a few families with an obscure and not very dangerous disease (alkaptonuria) to the realization that a whole territory of mysterious diseases might be understood as inherited disorders of metabolism. Working with William Bateson, Garrod came to understand the pattern of alkaptonuria appearance in children based on Mendelian principles. Once he applied Mendel’s concepts to alkaptonuria, he published a paper in 1902 called The Incidence of Alkaptonuria: A Study of Chemical Individuality. In the paper, Garrod explains how he came to understand the condition and speculates as to its causes. He cites various case studies and compares alkaptonuria to albinism in how it is inherited. He summarized his thoughts on the relationship of inheritance to metabolic disease in his book Inborn Errors of Metabolism .
F. G. Hopkins. 1938. Archibald Edward Garrod. 1857–1936. Biographical Memoirs of fellows of the Royal Society, 2:225–228.
Krishna Dronamraju. 1992. BIOGRAPHY Profiles in Genetics: Archibald E. Garrod (1857-1936). american Journal of Human Genetics, 51:216-219.
Nettie Marie Stevens
(1861–1912)
Source: Wikipedia
Nettie Maria Stevens was an early American geneticist. In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system.
Reginald Crundall Punnett
(1875–1967)
Source: Wikipedia
Reginald Crundall Punnett was a British geneticist who co-founded, with William Bateson, the Journal of Genetics in 1910. Punnett is probably best remembered today as the creator of the Punnett square, a tool still used by biologists to predict the probability of possible genotypes of offspring. His little book (62 small pages) Mendelism (1905) is sometimes said to have been the first textbook on genetics; it was probably the first popular science book to introduce genetics to the public.
Wilhelm Weinberg
(1862–1937)
Source: Wikipedia
Dr Wilhelm Weinberg was a German obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper, published in German in Jahresheft des Vereins für vaterländische Naturkunde in Württemberg (The Annals of the Society of National Natural History in Württemberg), expressed the concept that would later come to be known as the Hardy-Weinberg principle. Weinberg is also credited as the first to explain the effect of ascertainment bias on observations in genetics. Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the Verein für vaterländische Naturkunde in Württemberg (Society for the Natural History of the Fatherland in Württemberg), about six months before Hardy's paper was published in English. His lecture was printed later that year in the society's yearbook. Weinberg's contributions were unrecognized in the English speaking world for more than 35 years. Curt Stern, a German scientist who immigrated to the United States before World War II, pointed out in a brief paper in Science that Weinberg's exposition was both earlier and more comprehensive than Hardy's. Before 1943, the concepts in genetic equilibrium that are known today as the Hardy-Weinberg principle had been known as "Hardy's law" or "Hardy's formula" in English-language texts.
Godfrey Harold Hardy
(1877–1947)
Source: Wikipedia
Godfrey Harold "G. H." Hardy was an English mathematician, known for his achievements in number theory and mathematical analysis. In addition to his research, Hardy is remembered for his 1940 essay on the aesthetics of mathematics, entitled A Mathematician's Apology. He was the mentor of the Indian mathematician Srinivasa Ramanujan. Although every geneticist has heard of the Hardy-Weinberg Law and of Hardy-Weinberg Equilibrium, and although nearly all basic biology texts teach that G. H. Hardy played a seminal role in founding population genetics, most biologists don't realize that Hardy's total contribution to biology consisted of a single one-page letter to the editor in Science. The letter began, I am reluctant to intrude in a discussion concerning matters of which I have no expert knowledge, and I should have expected the very simple point which I wish to make to have been familiar to biologists. However, some remarks of Mr. Udny Yule, to which Mr. R. C. Punnett has called my attention, suggest that it may still be worth making. With that, Hardy offered his "simple point" and then washed his hands of biology. His autobiography, A Mathematician's Apology, makes no mention of population genetics. Mathematically, Hardy's "very simple point" was the trivial assertion that (p + q)2 = p2 + 2pq + q2 Biologically, however, Hardy's point was of greater consequence, as his simple algebra implied that Mendelian mechanisms, acting alone, have no effect upon allele frequencies in a population — an observation that was far from obvious to most biologists.
Hermann Joseph Muller
(1890–1967)
Source: Wikipedia
Hermann Joseph Muller (or H. J. Muller) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (Mutagenesis) as well as his outspoken political beliefs. Muller frequently warned of the long-term dangers of radioactive fallout from nuclear war and nuclear testing, helping to raise public awareness in this area. At 16 he entered Columbia College. From his first semester he was interested in biology; he became an early convert of the Mendelian-chromosome theory of heredity — and the concept of genetic mutations and natural selection as the basis for evolution. Muller remained at Columbia (the pre-eminent American zoology program at the time, thanks to E. B. Wilson and his students) for graduate school. He became interested in the Drosophila genetics work of Thomas Hunt Morgan's fly lab after undergraduate bottle washers Alfred Sturtevant and Calvin Bridges joined his Biology Club. He joined Morgan's group in 1912 (after two years of informal participation). In 1918, he proposed an explanation for the dramatic discontinuous alterations in Oenothera larmarckiana that were the basis of Hugo de Vries's theory of mutationism: "balanced lethals" allowed the accumulation of recessive mutations, and rare crossing over events resulted in the sudden expression of these hidden traits. In other words, de Vries's experiments were explainable by the Mendelian-chromosome theory.
Alfred Henry Sturtevant
(1891–1970)
Source: Wikipedia
Alfred Henry Sturtevant was an American geneticist. While still a student, Sturtevant constructed the first genetic map of a chromosome in 1913. Throughout his career he worked on the organism Drosophila melanogaster with Thomas Hunt Morgan. By watching the development of flies in which the earliest cell division produced two different genomes, he measured the embryonic distance between organs in a unit which is called the sturt in his honor. In 1965, Sturtevant published a first-rate, first-person account of A History of Genetics.
Edward B. Lewis. Alfred Henry Sturtevant November 21, 1891 – April 5, 1970. Biographical Memoirs of the National Academy of Science, 73:348–362.
Guide to the Alfred H. Sturtevant Papers, 1849-1969. Online Archive of California.
Calvin Blackman Bridges
(1889–1938)
Source: Wikipedia
Calvin Blackman Bridges was born in Schuyler Falls, New York in 1889 to the parents of Leonard Bridges and Charlotte Blackman. Tragically, Calvin's mother died when he was two years old, and his father died a year after his mother's death, leaving Calvin Bridges an orphan. Following the death of his parents, Bridges was taken in and raised by his grandmother. Despite now being known in the scientific world as one of the most influential researchers regarding Drosophila melanogaster, it took Bridges several years to complete high school, graduating when he was 20 years old. However, despite this setback, Bridges moved on to be an outstanding student at Columbia University, which he attended both for undergraduate and postgraduate school. While taking a zoology class, Bridges met Thomas Hunt Morgan. This started a relationship which would lead to many important discoveries in the scientific world regarding genetics and evolution. Bridges wrote a masterful Ph.D. thesis on Non-disjunction as proof of the chromosome theory of heredity (click HERE for part 2 ) which appeared as the first paper in the first issue of the journal Genetics in 1916. In this paper, he also established that the Y-chromosome does not determine gender in Drosophila.
Thomas Hunt Morgan
(1866–1945)
Source: Wikipedia
Thomas Hunt Morgan was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, Drosophila became a major model organism in contemporary genetics. The Division of Biology which he established at the California Institute of Technology has produced seven Nobel Prize winners.
Garland E. Allen. 1979. Thomas Hunt Morgan: The Man and His Science. Princeton: Princeton University Press. 447 pp. (The definitive biography)
Robert E. Kohler. 1994. Lords of the Fly: Drosophila Genetics and the Experimental Life. Chicago: University of Chicago Press. 344pp. (An excellent treatment of the early work in Drosophila genetics)
H. J. Muller. 1946. Thomas Hunt Morgan 1866–1945. Science, 103:550–551.
Diana E. Kenney and Gary G. Borisy. 2009. Thomas Hunt Morgan at the Marine Biological Laboratory: Naturalist and Experimentalist. Genetics, 181:841-846.
R. A. Fisher and G. R. de Beer. 1947. Thomas Hunt Morgan. 1866–1945. Obituary Notices of Fellows of the Royal Society, 5:451-466.
Stephen G. Brush. 2002. How Theories became Knowledge: Morgan's Chromosome Theory of Heredity in America and Britain. Journal of the History of Biology, 35:471–535.
Norman H. Horowitz. 1998. T. H. Morgan at Caltech: A Reminiscence. Genetics, 149:1629–1632.
John Burton Sanderson Haldane
(1892–1964)
Source: Wikipedia
John Burdon Sanderson Haldane was a British-born scientist known for his work in the study of physiology, genetics, evolutionary biology, and in mathematics, where he made innovative contributions to the fields of statistics and biostatistics. He was the son of the equally famous John Scott Haldane and was a professed socialist, Marxist, atheist, and humanist whose political dissent led him to leave England in 1956 and live in India, becoming a naturalised Indian citizen in 1961. His first paper in 1915 demonstrated genetic linkage in mammals while subsequent works helped to create population genetics, thus establishing a unification of Mendelian genetics and Darwinian evolution by natural selection whilst laying the groundwork for modern evolutionary synthesis. He was one of the three major figures to develop the mathematical theory of population genetics, along with Ronald Fisher and Sewall Wright. Thusly he played an important role in the modern evolutionary synthesis, which is popularly called "neo-Darwinism", as in Richard Dawkins' 1976 work titled The Selfish Gene. He re-established natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian inheritance. He wrote a series of ten papers called A Mathematical Theory of Natural and Artificial Selection, on the numerical formalism underpinning natural selection. It showed that gene frequencies have direction and rates of change; and he pioneered the interaction of natural selection with mutation and animal migration. Haldane's book, The Causes of Evolution (1932), summarised these results, especially in its extensive appendix. Arthur C. Clarke credited him as "perhaps the most brilliant science populariser of his generation". Nobel laureate Peter Medawar called Haldane "the cleverest man I ever knew".
Ronald Aylmer Fisher
(1890–1962)
Source: Wikipedia
Sir Ronald Aylmer Fisher, who published as R. A. Fisher, was an English statistician and biologist who used mathematics to combine Mendelian genetics and natural selection. This contributed to the revival of Darwinism in the early 20th century revision of the theory of evolution known as the modern synthesis. He was a prominent eugenicist in the early part of his life. In 1918 he published The Correlation Between Relatives on the Supposition of Mendelian Inheritance in 1918, in which he simultaneously resolved one of the outstanding debates in biology (the biometricians vs. the Mendelians) and introduced the idea of the analysis of variance. This paper was originally submitted to Biometrika where it was rejected, with a biological reviewer allowing that perhaps the mathematics had some value, but the biology was inconsequential while a statistical reviewer held the converse view. In 1925 he published Statistical Methods for Research Workers, one of the 20th century's most influential books on statistical methods. Fisher's method is a technique for data fusion or "meta-analysis" (analysis of analyses). This book also popularized the p-value, and it plays a central role in his approach. Fisher proposes the level p = 0.05, or a 1 in 20 chance of being exceeded by chance, as a limit for statistical significance, and applies this to a normal distribution (as a two-tailed test), thus yielding the rule of two standard deviations (on a normal distribution) for statistical significance. In 1933 he became Professor of Eugenics at University College London until 1939 when the department was dissolved. In 1935, he published by The Design of Experiments, which was also fundamental, [and promoted] statistical technique and application. In this book Fisher also outlined the Lady tasting tea, now a famous design of a statistical randomized experiment which uses Fisher's exact test and is the original exposition of Fisher's notion of a null hypothesis. In 1936 he published Has Mendel's Work Been Rediscovered?, in which he suggested that Mendel's results were too good to be true and that someone (perhaps an over-eager assistant) had fudged the results.
Sewall Wright
(1889–1988)
Source: Wikipedia
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. He was a founder of population genetics alongside Ronald Fisher and J.B.S. Haldane, which was a major step in the development of the modern evolutionary synthesis combining genetics with evolution. He discovered the inbreeding coefficient and methods of computing it in pedigree animals. He extended this work to populations, computing the amount of inbreeding between members of populations as a result of random genetic drift, and along with Fisher he pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. Wright also made major contributions to mammalian and biochemical genetics. His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. In this work he also introduced the concept of effective population size. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or evolutionary landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.
Theophilus S. Painter
(1889–1969)
Source: Wikipedia
Theophilus Shickel Painter was an American zoologist best-known for his work on the structure and function of chromosomes, especially the sex-determination genes X and Y in humans. He also carried out work in identifying genes in fruit flies (Drosophila). His work exploited the giant polytene chromosomes in the salivary glands of Drosophila and other Dipteran larvae. Painter joined the faculty at the University of Texas in 1916 and, except for military duty during World War I, stayed there his whole career. He was, in succession, associate professor, professor and distinguished professor of zoology. He served as acting president (1944–1946) and president (1946–1952) of the University of Texas and retired from active teaching in 1966.
Ching Chun Li
(1912–2003)
Source: Wikipedia
Ching Chun Li was a respected American population geneticist and human geneticist. Li was best known for his book An Introduction to Population Genetics and his teaching in human genetics. Ching Chun Li was born on October 27, 1912, in Taku, Tianjin, China. He received his BS degree in agronomy from the University of Nanking in 1936 and a PhD in plant breeding and genetics from Cornell University in 1940. He worked as post-doctorate fellows at Columbia University and North Carolina State University from 1940 to 1941. Li returned to China at the age of 30 and became the Professor of Genetics and Biometry at University of Nanking, his alma mater, in 1943. After World War II, he moved to Beijing for a Professorship of Agronomy at Peking University in 1946, where he finished An Introduction to Population Genetics in 1948. The book was the first notable publication where the population-genetics ideas of Ronald Fisher, Sewall Wright, and J. B. S. Haldane were brought together, synthesized, and presented in a coherent and readily understood manner.
Aravinda Chakravarti. 2004. Ching Chun Li (1912–2003):A Personal Remembrance of a Hero of Genetics The American Journal of Human Genetics, 74:789-792.
Eliot B. Spiess. 2005. Remembrance of Ching Chun Li, 1912–2003 Genetics, 169:9-11.
Erwin Chargaff
(1905–2002)
Source: Wikipedia
Erwin Chargaff (11 August 1905 – 20 June 2002) was an Austro-Hungarian biochemist that immigrated to the United States during the Nazi era and was a professor of biochemistry at Columbia University medical school. Through careful experimentation, Chargaff made two observations that helped to disprove the tetranucleotide model of DNA. Under the tetranucleotide hypothesis, it was assumed that DNA was built as a simple repeating polymer of units consisting of one adenine, one thymine, one cytosine, and one guanine. Such a structure would mean that all DNA molecules has essentially the same structure, differeing only in length. Such a molecule would be incapable of carrying hereditary information. Chargaff's observations: (1) the percent nucleotide composition of DNA was not exactly 25% of each nucleotide, (2) the percent nucleotide composition of DNA differed (slightly) from one species to another, and (3) the percent nucleotide composition of DNA was constant within a species. He also observed regular numerical patterns in the nucleotide makeup of any DNA sample. The two best remembered patterns are that, in any DNA sample, the amount of adenine always equals the amount of thymine, and the amount of guanine always equals the amount of cytosine. These observations, especially the A-T and C-G equalities, helped Watson and Crick devise the double-helix model of DNA. Chargaff had a quick wit and a sharp pen and he was not impressed with advances made through theory rather than through laboratory work. He once commented that Molecular biology is essentially the practice of biochemistry without a license.
Francis Crick
(1916–2004)
Source: Wikipedia
Francis Harry Compton Crick was a British molecular biologist, biophysicist, and neuroscientist, most noted for being a co-discoverer of the structure of the DNA molecule in 1953 with James Watson. Together with Watson and Maurice Wilkins, he was jointly awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". Crick was an important theoretical molecular biologist and played a crucial role in research related to revealing the helical structure of DNA. He is widely known for use of the term "central dogma" to summarize the idea that genetic information flow in cells is essentially one-way, from DNA to RNA to protein. During the remainder of his career, he held the post of J.W. Kieckhefer Distinguished Research Professor at the Salk Institute for Biological Studies in La Jolla, California. His later research centered on theoretical neurobiology and attempts to advance the scientific study of human consciousness. He remained in this post until his death; "he was editing a manuscript on his death bed, a scientist until the bitter end" according to Christof Koch.
James Dewey Watson
(1928– )
Source: Wikipedia
James Dewey Watsonis an American molecular biologist, geneticist and zoologist, best known as one of the co-discoverers of the structure of DNA in 1953 with Francis Crick. Watson, Crick, and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". From 1956 to 1976, Watson was on the faculty of the Harvard University Biology Department, promoting research in molecular biology. From 1968 he served as director of Cold Spring Harbor Laboratory (CSHL), greatly expanding its level of funding and research. At CSHL, he shifted his research emphasis to the study of cancer, along with making it a world leading research center in molecular biology. In 1994, he started as president and served for 10 years. He was then appointed chancellor, serving until he resigned in 2007. Between 1988 and 1992, Watson was associated with the National Institutes of Health, helping to establish the Human Genome Project.
Carl Woese
(1928–2012)
Source: Wikipedia
Carl Richard Woese was an American microbiologist and biophysicist. Woese is famous for defining the Archaea (a new domain or kingdom of life) in 1977 by phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese which revolutionized the discipline of microbiology. He was also the originator of the RNA world hypothesis in 1967, although not by that name. He held the Stanley O. Ikenberry Chair and was professor of microbiology at the University of Illinois at Urbana–Champaign. For much of the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry, morphology and metabolism. In a highly influential 1962 paper, Roger Stanier and C. B. van Niel first established the division of cellular organization into prokaryotes and eukaryotes, defining prokaryotes as those organisms lacking a cell nucleus. Stanier and Van Niel's concept was quickly accepted as the most important distinction among organisms; yet they were nevertheless skeptical of microbiologists' attempts to construct a natural phylogenetic classification of bacteria. However, it became generally assumed that all life shared a common prokaryotic (implied by the Greek root pro- (before, in front of) ancestor. In 1977, Carl Woese and George E. Fox experimentally disproved this universally held hypothesis about the basic structure of the tree of life. Woese and Fox discovered a kind of microbial life which they called the “archaebacteria” (Archaea). They reported that the archaebacteria comprised "a third kingdom" of life as distinct from bacteria as plants and animals. Having defined Archaea as a new "urkingdom" (later domain) which were neither bacteria nor eukaryotes, Woese redrew the taxonomic tree. His three-domain system, based on phylogenetic relationships rather than obvious morphological similarities, divided life into 23 main divisions, incorporated within three domains: Bacteria, Archaea, and Eucarya.
Looking in the Right Direction: Carl Woese and the New Biology
Pierre-Louis Maupertuis
(1698–1759)
Source: Wikipedia
Pierre Louis Moreau de Maupertuis was a French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Prussian Academy of Science, at the invitation of Frederick the Great. His work in natural history is interesting in relation to modern science, since he touched on aspects of heredity and the struggle for life. Some historians of science point to his work in biology as a significant precursor to the development of evolutionary theory, specifically the theory of natural selection. Other writers contend that his remarks are cursory, vague, or incidental to that particular argument. Mayr's verdict was "He was neither an evolutionist, nor one of the founders of the theory of natural selection [but] he was one of the pioneers of genetics". Maupertuis espoused a theory of pangenesis, postulating particles from both mother and father as responsible for the characters of the child. Bowler credits him with studies on heredity, with the natural origin of human races, and with the idea that forms of life may have changed with time.
Joseph Gottlieb Kölreuter
(1733–1806)
Source: Wikipedia
Joseph Gottlieb Kölreuter, also spelled Koelreuter or Kohlreuter, was a German botanist who pioneered the study of plant fertilization, hybridization and was the first to detect self-incompatibility. He was an observer as well as a rigorous experimenter who used careful crossing experiments although he did not inquire into the nature of heritability. Kölreuter was the oldest of three sons of an apothecary in Karlsruhe, Germany, and grew up in Sulz. He took an early interest in natural history and made a collection of local insects. At the age of fifteen he went to study medicine at the University of Tübingen under physician and botanist Johann Georg Gmelin who had returned from St. Petersburg. Gmelin had an interest in floral biology and he reprinted a work by Rudolf Jakob Camerarius (who also taught at Tübingen) who was the first to demonstrate sexual reproduction in plants. In his inaugural address in 1749 Gmelin talked the need for research on the origin of new species by hybridization. Kölreuter major works were produced as four reports Vorlaufige Nachricht von einigen das Geschlecht der Pflanzen betreffenden Versuchen und Beobachtungen (1761), Fortsetzung (1763), Zweyte Fortsetzung (1764), and Dritte Fortsetzung (1766). In all he conducted nearly 500 different hybridization experiments across 138 species and examined the pollen characteristics of over a 1000 plant species.
Ernst Mayr. 1986. Joseph Gottlieb Kölreuter's Contributions to Biology. Osiris, 2:135-176.
Charles Darwin
(1809–1882)
Source: Wikipedia
Charles Robert Darwin was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. He established that all species of life have descended over time from common ancestors and, in a joint publication with Alfred Russel Wallace, introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s, the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.
Darwin Online: The world's largest and most widely used resource on Darwin, containing his complete publications, his private papers and manuscripts, and much supplementary material.
Carl Nägeli
(1817–1891)
Source: Wikipedia
Carl Wilhelm von Nägeli was a Swiss botanist. He studied cell division and pollination but became known as the man who discouraged Gregor Mendel from further work on genetics. He rejected natural selection as a mechanism of evolution, favouring orthogenesis driven by a supposed "inner perfecting principle". The writer Simon Mawer, in his book Gregor Mendel: Planting the Seeds of Genetics (2006), gives us an interesting and detailed account of Nägeli's correspondence with Mendel. Mawer underlines that, at the time Nägeli was writing to the friar from Moravia, Nägeli "must have been preparing his great work entitled A mechanico-physiological theory of organic evolution (published in 1884, the year of Mendel's death) in which he proposes the concept of the 'idioplasm' as the hypothetical transmitter of inherited characters". Mawer notes that, in this Nägeli book, there is not a single mention of the work of Gregor Mendel. That prompted him to write: "We can forgive von Nägeli for being obtuse and supercilious. We can forgive him for being ignorant, a scientist of his time who did not really have the equipment to understand the significance of what Mendel had done despite the fact that he (von Nägeli) speculated extensively about inheritance. But omitting an account of Mendel's work from his book is, perhaps, unforgivable." (Mawer 2006, p. 81)
Francis Galton
(1822–1911)
Source: Wikipedia
Sir Francis Galton was an English Victorian statistician, progressive, polymath, sociologist, psychologist, anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, and psychometrician. He was knighted in 1909. Galton produced over 340 papers and books. He also created the statistical concept of correlation and widely promoted regression toward the mean. He was the first to apply statistical methods to the study of human differences and inheritance of intelligence, and introduced the use of questionnaires and surveys for collecting data on human communities, which he needed for genealogical and biographical works and for his anthropometric studies.
GALTON.ORG — An extensive on-line collection, providing a biography, Galton's collected works, and more.
The Francis Galton Papers: A collection of digitized resources maintained by the Wellcome Library (part of the Wellcome Trust)
Friedrich Miescher
(1844–1895)
Source: Wikipedia
Johannes Friedrich Miescher was a Swiss physician and biologist. He was the first researcher to isolate nucleic acid. Miescher isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in 1869 in Felix Hoppe-Seyler's laboratory at the University of Tübingen, Germany, paving the way for the identification of DNA as the carrier of inheritance. The significance of the discovery, first published in 1871, was not at first apparent, and it was Albrecht Kossel who made the initial inquiries into its chemical structure. Later, Friedrich Miescher raised the idea that the nucleic acids could be involved in heredity.
Ralf Dahm. 2008. Discovering DNA: Friedrich Miescher and the early years of nucleic acid research. Human Genetics, 122:565. doi:10.1007/s00439-007-0433-0
William Keith Brooks
(1848–1908)
Source: Wikipedia
William Keith Brooks received a Bachelor of Arts degree from Williams College in 1870 and a PhD from Harvard in 1875. With the opening of The Johns Hopkins University in 1876, Brooks received one of the university's initial fellowships and he quickly advanced within the organization, ultimately serving as Professor of Zoology and Head of the Biological Department. At the young age of 36 he was elected a member of the National Academy. He was chosen as a member of the American Philosophical Society in 1886 and of the Academy of Natural Science in 1887. Although many of Brooks' scientific contributions represent solid, nineteeth-century work, his most lasting effect came from his long-standing conviction that the processes of heredity were themselves a proper subject of investigation. In 1876 he wrote a paper entitled "A Provisional Hypothesis of Pangenesis" and he gave the subject a book-length treatment in his The Law of Heredity. A Study of the Cause of Variation and the Origin of Living Organisms. He was known as both a man of deep, abstract thought and an excellent teacher, as evidenced by the fact that many of the still well-known pioneers of genetics had, at one time or another, studied with him: viz. Thomas Morgan, E. B. Wilson, and William Bateson.
Eduard Strasburger
(1844–1912)
Source: Wikipedia
Eduard Adolf Strasburger was a Polish-German professor who was one of the most famous botanists of the 19th century. Strasburger studied biological sciences in Paris, Bonn and Jena, receiving a PhD in 1866 after working with Nathanael Pringsheim. In 1868 he taught at the University of Warsaw. In 1869 he was appointed professor of botany at the University of Jena. Since 1881 he was head of the Botanisches Institut at the University of Bonn. Together with Walther Flemming, and Edouard van Beneden he elucidated chromosome distribution during cell division.
Walther Flemming
(1843–1905)
Source: Wikipedia
Walther Flemming was a German biologist and a founder of cytogenetics. Flemming trained in medicine at University of Rostock, graduating in 1868. Afterwards, he served in 1870–71 as a military physician in the Franco-Prussian War. From 1873 to 1876 he worked as a teacher at the University of Prague. In 1876 he accepted a post as a professor of anatomy at the University of Kiel. He became the director of the Anatomical Institute and stayed there until his death. With the use of aniline dyes he was able to find a structure which strongly absorbed basophilic dyes, which he named chromatin. He identified that chromatin was correlated to threadlike structures in the cell nucleus – the chromosomes (meaning coloured bodies), which were named thus later by German anatomist Wilhelm von Waldeyer-Hartz (1841–1923). The Belgian scientist Edouard Van Beneden (1846–1910) had also independently observed chromosomes. Flemming investigated the process of cell division and the distribution of chromosomes to the daughter nuclei, a process he called mitosis from the Greek word for thread. However, he did not see the splitting into identical halves, the daughter chromatids. He studied mitosis both in vivo and in stained preparations, using as the source of biological material the fins and gills of salamanders. These results were published first in 1878 and in 1882 in the seminal book Zellsubstanz, Kern und Zelltheilung (Cell substance, nucleus and cell division). On the basis of his discoveries, Flemming surmised for the first time that all cell nuclei came from another predecessor nucleus (he coined the phrase omnis nucleus e nucleo, after Virchow's omnis cellula e cellula).
Neidhard Paweletz. 2001. Walther Flemming: pioneer of mitosis research. Nature Reviews Molecular Cell Biology, 2:72-75. | doi:10.1038/35048077
Édouard Joseph Louis Marie van Beneden
(1846–1910)
Source: Wikipedia
Édouard Joseph Louis Marie Van Beneden was a Belgian embryologist, cytologist and marine biologist. He was professor of zoology at the University of Liège. He contributed to cytogenetics by his works on the roundworm Ascaris. In this work he discovered and described the process of meiosis — a two-cell-division process by which cells reduce the number of chromosomes in preparation for the production of gametes. Van Beneden also elucidated, together with Walther Flemming and Eduard Strasburger, the essential facts of mitosis — the single-cell-division process that distributes equal chromosome complements to each of the two daughter cells.
Heinrich Wilhelm Gottfried von Waldeyer-Hartz
(1836–1921)
Source: Wikipedia
Heinrich Wilhelm Gottfried von Waldeyer-Hartz was a German anatomist, famous for consolidating the neuron theory of organization of the nervous system and for naming the chromosome. He is also remembered in two macroanatomical structures of the human body which were named after him: Waldeyer's tonsillar ring (the lymphoid tissue ring of the naso- and oropharynx) and Waldeyer's glands (of the eyelids). Waldeyer also studied the basophilic stained filaments which had been found (by his colleague of Kiel, Walther Flemming) to be the main constituents of chromatin, the material inside the cell nucleus. Although the full significance of chromosomes for genetics and for cell biology was still to be discovered, these filaments were known to be involved in the phenomenon of cell division discovered by Flemming, named mitosis, as well as in meiosis. In 1888, Waldeyer coined the term chromosome — colored body — to describe them.
T. Cremer and C. Cremer. 1988. Centennial of Wilhelm Waldeyer’s introduction of the term “chromosome” in 1888. Cytogenetics and Cell Genetics, 48:66–67. (DOI:10.1159/000132591)
Waldeyer's 1888 paper in which he uses the word chromosome: Über Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen.
August Weismann
(1834–1914)
Source: Wikipedia
August Friedrich Leopold Weismann was a German evolutionary biologist. Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg. His main contribution involved his Germ Plasm Theory, at one time also known as Weismannism, according to which inheritance (in a multicellular organism) only takes place by means of the germ cells — the gametes such as egg cells and sperm cells. Other cells of the body — somatic cells — do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck. The idea of the Weismann barrier is central to the modern evolutionary synthesis, though scholars do not express it today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann became one of the first biologists to deny Lamarckism entirely. Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection. Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–1940, and "one of the great biologists of all time".
Essays Upon Heredity — a collection of Weismann's writing on hereditary issues.
Yawen Zou. 2015. The Germ-Plasm: a Theory of Heredity (1893), by August Weismann. The Embryo Project Encyclopedia.
Edwin G. Conklin. 1915. August Weismann. Proceedings of the American Philosophical Society, 54:3-12.
Edmund Beecher Wilson
(1856–1939)
Source: Wikipedia
Edmund Beecher Wilson was a pioneering American zoologist and geneticist. He wrote one of the most famous textbooks in the history of modern biology, The Cell in Development and Inheritance. He and Nettie Maria Stevens were the first researchers to describe the chromosomal basis of sex, but they conducted their research independently of each other. Wilson is credited as America's first cell biologist. In 1898 he used the similarity in embryos to describe phylogenetic relationships. By observing spiral cleavage in molluscs, flatworms and annelids he concluded that the same organs came from the same group of cells and concluded that all these organisms must have a common ancestor.
Erich von Tschermak
(1864–1933)
Source: Wikipedia
Erich Tschermak, Edler von Seysenegg was an Austrian agronomist who developed several new disease-resistant crops, including wheat-rye and oat hybrids. He was a son of the Moravia-born mineralogist Gustav Tschermak von Seysenegg. His maternal grandfather was the famous botanist, Eduard Fenzl, who taught Gregor Mendel botany during his student days in Vienna.
Hugo de Vries
(1848–1935)
Source: Wikipedia
Hugo Marie de Vries was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution. In 1889, De Vries published his book Intracellular Pangenesis, in which, based on a modified version of Charles Darwin's theory of Pangenesis of 1868, he postulated that different characters have different hereditary carriers. He specifically postulated that inheritance of specific traits in organisms comes in particles. He called these units pangenes, a term 20 years later to be shortened to genes by Wilhelm Johannsen.
Ralph E. Cleland. 1936. Hugo de Vries. Proceedings of the American Philosophical Society, 76:248-250.
William Bateson
(1861–1926)
Source: Wikipedia
William Bateson was an English biologist who was the first person to use the term genetics to describe the study of heredity, and the chief populariser of the ideas of Gregor Mendel following their rediscovery in 1900 by Hugo de Vries and Carl Correns. Bateson first suggested using the word "genetics" to describe the study of inheritance and the science of variation in a personal letter to Adam Sedgwick who had been Darwin's professor), dated 18 April 1905. Bateson first used the term "genetics" publicly at the Third International Conference on Plant Hybridization in London in 1906.
Carl Correns
(1864–1933)
Source: Wikipedia
Carl Erich Correns was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendel's earlier paper on that subject, which he achieved simultaneously but independently of the botanists Erich Tschermak von Seysenegg and Hugo de Vries, and the agronomist William Jasper Spillman. Carl Correns conducted much of the foundational work for the field of genetics at the turn of the 20th century. He rediscovered and independently verified the work of Mendel in a separate model organism. He also discovered cytoplasmic inheritance, an important extension of Mendel's theories, which demonstrated the existence of extra-chromosomal factors on phenotype. Most of Correns' work went unpublished however, and was destroyed in the Berlin bombings of 1945.
Theodor Boveri
(1862–1915)
Source: Embryo Project
Theodor Heinrich Boveri was a German biologist. He was notable for first hypothesising the cellular processes that cause cancer. Boveri's work with sea urchins showed that it was necessary to have all chromosomes present in order for proper embryonic development to take place. This discovery was an important part of the Boveri–Sutton chromosome theory, which identifies chromosomes as the carriers of genetic material. The theory correctly explains the mechanism underlying the laws of Mendelian inheritance by identifying chromosomes with the paired factors (particles) required by Mendel's laws. The chromosome theory of inheritance is credited to papers by Walter Sutton in 1902 and 1903, as well as to independent work by Theodor Boveri during roughly the same period. Boveri's thoughts are summarized in his book Ergebnisse über die Konstitution der chromatischen Substanz des Zellkerns (Results on the constitution of the chromatic substance of the cell nucleus), Jena: Verlag von Gustav Fischer, 1904. His other significant discovery was the centrosome (1888), which he described as the especial organ of cell division. Boveri also discovered the phenomenon of chromatin diminution during embryonic development of the nematode Parascaris.
Clarence Erwin McClung
(1870–1946)
Source: Wikipedia
Clarence Erwin (CE) McClung was an American zoologist of wide-ranging interests. Although born in California, he spent much of his early life in Kansas. He originally studied pharmacy at Kansas University, receiving the Ph.G. degree in 1892. He taught pharmacy at the University for a year, but then his interest shifted to more general biological questions and he reenrolled as a student. From Kansas University he received the A.B. degree in 1896, the A.M. in 1898, and the Ph.D. in 1902. CE McClung made important contributions to early genetics, but he was also a general zoologist and paleontologist who received all of his degrees from Kansas and then spent his early career on the faculty there, ultimately assuming the positions of chair of the zoology department, curator of vertebrate paleontology, and even acting dean of the medical school. Early in his career, he undertook an investigation of spermatogenesis in Ziphidium fasciatum, a long-horned grasshopper. In this material he recognized that an object thought by some to be a nucleolus was actually an unpaired chromosome. Although others had noticed that this object was distributed asymmetrically into some but not all spermatozoa, McClung was the first to see that this could provide a cytological mechanism of sex determination.
D. H. Wenrich. 1946. Clarence Erwin McClung 1870-1946 Science, 103:551-552. DOI: 10.1126/science.103.2679.551
David Henry Wenrich Papers: A collection largely developed to support the Dr. Wenrich's efforts to honor Dr. Clarence Erwin McClung.
Archibald Garrod
(1857–1938)
Source: Wikipedia
Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. He also discovered alkaptonuria, understanding its inheritance. He served as Regius Professor of Medicine at the University of Oxford from 1920 to 1927. Garrod is best known for his scientific study of inborn errors of metabolism. He developed an increasing interest in chemical pathology, and investigated urine chemistry as a reflection of systemic metabolism and disease. This research, combined with the new understanding of Mendelian inheritance, evolved from an investigation of a few families with an obscure and not very dangerous disease (alkaptonuria) to the realization that a whole territory of mysterious diseases might be understood as inherited disorders of metabolism. Working with William Bateson, Garrod came to understand the pattern of alkaptonuria appearance in children based on Mendelian principles. Once he applied Mendel’s concepts to alkaptonuria, he published a paper in 1902 called The Incidence of Alkaptonuria: A Study of Chemical Individuality. In the paper, Garrod explains how he came to understand the condition and speculates as to its causes. He cites various case studies and compares alkaptonuria to albinism in how it is inherited. He summarized his thoughts on the relationship of inheritance to metabolic disease in his book Inborn Errors of Metabolism .
F. G. Hopkins. 1938. Archibald Edward Garrod. 1857–1936. Biographical Memoirs of fellows of the Royal Society, 2:225–228.
Krishna Dronamraju. 1992. BIOGRAPHY Profiles in Genetics: Archibald E. Garrod (1857-1936). american Journal of Human Genetics, 51:216-219.
Nettie Marie Stevens
(1861–1912)
Source: Wikipedia
Nettie Maria Stevens was an early American geneticist. In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system.
Reginald Crundall Punnett
(1875–1967)
Source: Wikipedia
Reginald Crundall Punnett was a British geneticist who co-founded, with William Bateson, the Journal of Genetics in 1910. Punnett is probably best remembered today as the creator of the Punnett square, a tool still used by biologists to predict the probability of possible genotypes of offspring. His little book (62 small pages) Mendelism (1905) is sometimes said to have been the first textbook on genetics; it was probably the first popular science book to introduce genetics to the public.
Wilhelm Weinberg
(1862–1937)
Source: Wikipedia
Dr Wilhelm Weinberg was a German obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper, published in German in Jahresheft des Vereins für vaterländische Naturkunde in Württemberg (The Annals of the Society of National Natural History in Württemberg), expressed the concept that would later come to be known as the Hardy-Weinberg principle. Weinberg is also credited as the first to explain the effect of ascertainment bias on observations in genetics. Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the Verein für vaterländische Naturkunde in Württemberg (Society for the Natural History of the Fatherland in Württemberg), about six months before Hardy's paper was published in English. His lecture was printed later that year in the society's yearbook. Weinberg's contributions were unrecognized in the English speaking world for more than 35 years. Curt Stern, a German scientist who immigrated to the United States before World War II, pointed out in a brief paper in Science that Weinberg's exposition was both earlier and more comprehensive than Hardy's. Before 1943, the concepts in genetic equilibrium that are known today as the Hardy-Weinberg principle had been known as "Hardy's law" or "Hardy's formula" in English-language texts.
Godfrey Harold Hardy
(1877–1947)
Source: Wikipedia
Godfrey Harold "G. H." Hardy was an English mathematician, known for his achievements in number theory and mathematical analysis. In addition to his research, Hardy is remembered for his 1940 essay on the aesthetics of mathematics, entitled A Mathematician's Apology. He was the mentor of the Indian mathematician Srinivasa Ramanujan. Although every geneticist has heard of the Hardy-Weinberg Law and of Hardy-Weinberg Equilibrium, and although nearly all basic biology texts teach that G. H. Hardy played a seminal role in founding population genetics, most biologists don't realize that Hardy's total contribution to biology consisted of a single one-page letter to the editor in Science. The letter began, I am reluctant to intrude in a discussion concerning matters of which I have no expert knowledge, and I should have expected the very simple point which I wish to make to have been familiar to biologists. However, some remarks of Mr. Udny Yule, to which Mr. R. C. Punnett has called my attention, suggest that it may still be worth making. With that, Hardy offered his "simple point" and then washed his hands of biology. His autobiography, A Mathematician's Apology, makes no mention of population genetics. Mathematically, Hardy's "very simple point" was the trivial assertion that (p + q)2 = p2 + 2pq + q2 Biologically, however, Hardy's point was of greater consequence, as his simple algebra implied that Mendelian mechanisms, acting alone, have no effect upon allele frequencies in a population — an observation that was far from obvious to most biologists.
Hermann Joseph Muller
(1890–1967)
Source: Wikipedia
Hermann Joseph Muller (or H. J. Muller) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (Mutagenesis) as well as his outspoken political beliefs. Muller frequently warned of the long-term dangers of radioactive fallout from nuclear war and nuclear testing, helping to raise public awareness in this area. At 16 he entered Columbia College. From his first semester he was interested in biology; he became an early convert of the Mendelian-chromosome theory of heredity — and the concept of genetic mutations and natural selection as the basis for evolution. Muller remained at Columbia (the pre-eminent American zoology program at the time, thanks to E. B. Wilson and his students) for graduate school. He became interested in the Drosophila genetics work of Thomas Hunt Morgan's fly lab after undergraduate bottle washers Alfred Sturtevant and Calvin Bridges joined his Biology Club. He joined Morgan's group in 1912 (after two years of informal participation). In 1918, he proposed an explanation for the dramatic discontinuous alterations in Oenothera larmarckiana that were the basis of Hugo de Vries's theory of mutationism: "balanced lethals" allowed the accumulation of recessive mutations, and rare crossing over events resulted in the sudden expression of these hidden traits. In other words, de Vries's experiments were explainable by the Mendelian-chromosome theory.
Alfred Henry Sturtevant
(1891–1970)
Source: Wikipedia
Alfred Henry Sturtevant was an American geneticist. While still a student, Sturtevant constructed the first genetic map of a chromosome in 1913. Throughout his career he worked on the organism Drosophila melanogaster with Thomas Hunt Morgan. By watching the development of flies in which the earliest cell division produced two different genomes, he measured the embryonic distance between organs in a unit which is called the sturt in his honor. In 1965, Sturtevant published a first-rate, first-person account of A History of Genetics.
Edward B. Lewis. Alfred Henry Sturtevant November 21, 1891 – April 5, 1970. Biographical Memoirs of the National Academy of Science, 73:348–362.
Guide to the Alfred H. Sturtevant Papers, 1849-1969. Online Archive of California.
Calvin Blackman Bridges
(1889–1938)
Source: Wikipedia
Calvin Blackman Bridges was born in Schuyler Falls, New York in 1889 to the parents of Leonard Bridges and Charlotte Blackman. Tragically, Calvin's mother died when he was two years old, and his father died a year after his mother's death, leaving Calvin Bridges an orphan. Following the death of his parents, Bridges was taken in and raised by his grandmother. Despite now being known in the scientific world as one of the most influential researchers regarding Drosophila melanogaster, it took Bridges several years to complete high school, graduating when he was 20 years old. However, despite this setback, Bridges moved on to be an outstanding student at Columbia University, which he attended both for undergraduate and postgraduate school. While taking a zoology class, Bridges met Thomas Hunt Morgan. This started a relationship which would lead to many important discoveries in the scientific world regarding genetics and evolution. Bridges wrote a masterful Ph.D. thesis on Non-disjunction as proof of the chromosome theory of heredity (click HERE for part 2 ) which appeared as the first paper in the first issue of the journal Genetics in 1916. In this paper, he also established that the Y-chromosome does not determine gender in Drosophila.
Thomas Hunt Morgan
(1866–1945)
Source: Wikipedia
Thomas Hunt Morgan was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, Drosophila became a major model organism in contemporary genetics. The Division of Biology which he established at the California Institute of Technology has produced seven Nobel Prize winners.
Garland E. Allen. 1979. Thomas Hunt Morgan: The Man and His Science. Princeton: Princeton University Press. 447 pp. (The definitive biography)
Robert E. Kohler. 1994. Lords of the Fly: Drosophila Genetics and the Experimental Life. Chicago: University of Chicago Press. 344pp. (An excellent treatment of the early work in Drosophila genetics)
H. J. Muller. 1946. Thomas Hunt Morgan 1866–1945. Science, 103:550–551.
Diana E. Kenney and Gary G. Borisy. 2009. Thomas Hunt Morgan at the Marine Biological Laboratory: Naturalist and Experimentalist. Genetics, 181:841-846.
R. A. Fisher and G. R. de Beer. 1947. Thomas Hunt Morgan. 1866–1945. Obituary Notices of Fellows of the Royal Society, 5:451-466.
Stephen G. Brush. 2002. How Theories became Knowledge: Morgan's Chromosome Theory of Heredity in America and Britain. Journal of the History of Biology, 35:471–535.
Norman H. Horowitz. 1998. T. H. Morgan at Caltech: A Reminiscence. Genetics, 149:1629–1632.
John Burton Sanderson Haldane
(1892–1964)
Source: Wikipedia
John Burdon Sanderson Haldane was a British-born scientist known for his work in the study of physiology, genetics, evolutionary biology, and in mathematics, where he made innovative contributions to the fields of statistics and biostatistics. He was the son of the equally famous John Scott Haldane and was a professed socialist, Marxist, atheist, and humanist whose political dissent led him to leave England in 1956 and live in India, becoming a naturalised Indian citizen in 1961. His first paper in 1915 demonstrated genetic linkage in mammals while subsequent works helped to create population genetics, thus establishing a unification of Mendelian genetics and Darwinian evolution by natural selection whilst laying the groundwork for modern evolutionary synthesis. He was one of the three major figures to develop the mathematical theory of population genetics, along with Ronald Fisher and Sewall Wright. Thusly he played an important role in the modern evolutionary synthesis, which is popularly called "neo-Darwinism", as in Richard Dawkins' 1976 work titled The Selfish Gene. He re-established natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian inheritance. He wrote a series of ten papers called A Mathematical Theory of Natural and Artificial Selection, on the numerical formalism underpinning natural selection. It showed that gene frequencies have direction and rates of change; and he pioneered the interaction of natural selection with mutation and animal migration. Haldane's book, The Causes of Evolution (1932), summarised these results, especially in its extensive appendix. Arthur C. Clarke credited him as "perhaps the most brilliant science populariser of his generation". Nobel laureate Peter Medawar called Haldane "the cleverest man I ever knew".
Ronald Aylmer Fisher
(1890–1962)
Source: Wikipedia
Sir Ronald Aylmer Fisher, who published as R. A. Fisher, was an English statistician and biologist who used mathematics to combine Mendelian genetics and natural selection. This contributed to the revival of Darwinism in the early 20th century revision of the theory of evolution known as the modern synthesis. He was a prominent eugenicist in the early part of his life. In 1918 he published The Correlation Between Relatives on the Supposition of Mendelian Inheritance in 1918, in which he simultaneously resolved one of the outstanding debates in biology (the biometricians vs. the Mendelians) and introduced the idea of the analysis of variance. This paper was originally submitted to Biometrika where it was rejected, with a biological reviewer allowing that perhaps the mathematics had some value, but the biology was inconsequential while a statistical reviewer held the converse view. In 1925 he published Statistical Methods for Research Workers, one of the 20th century's most influential books on statistical methods. Fisher's method is a technique for data fusion or "meta-analysis" (analysis of analyses). This book also popularized the p-value, and it plays a central role in his approach. Fisher proposes the level p = 0.05, or a 1 in 20 chance of being exceeded by chance, as a limit for statistical significance, and applies this to a normal distribution (as a two-tailed test), thus yielding the rule of two standard deviations (on a normal distribution) for statistical significance. In 1933 he became Professor of Eugenics at University College London until 1939 when the department was dissolved. In 1935, he published by The Design of Experiments, which was also fundamental, [and promoted] statistical technique and application. In this book Fisher also outlined the Lady tasting tea, now a famous design of a statistical randomized experiment which uses Fisher's exact test and is the original exposition of Fisher's notion of a null hypothesis. In 1936 he published Has Mendel's Work Been Rediscovered?, in which he suggested that Mendel's results were too good to be true and that someone (perhaps an over-eager assistant) had fudged the results.
Sewall Wright
(1889–1988)
Source: Wikipedia
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. He was a founder of population genetics alongside Ronald Fisher and J.B.S. Haldane, which was a major step in the development of the modern evolutionary synthesis combining genetics with evolution. He discovered the inbreeding coefficient and methods of computing it in pedigree animals. He extended this work to populations, computing the amount of inbreeding between members of populations as a result of random genetic drift, and along with Fisher he pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. Wright also made major contributions to mammalian and biochemical genetics. His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. In this work he also introduced the concept of effective population size. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or evolutionary landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.
Theophilus S. Painter
(1889–1969)
Source: Wikipedia
Theophilus Shickel Painter was an American zoologist best-known for his work on the structure and function of chromosomes, especially the sex-determination genes X and Y in humans. He also carried out work in identifying genes in fruit flies (Drosophila). His work exploited the giant polytene chromosomes in the salivary glands of Drosophila and other Dipteran larvae. Painter joined the faculty at the University of Texas in 1916 and, except for military duty during World War I, stayed there his whole career. He was, in succession, associate professor, professor and distinguished professor of zoology. He served as acting president (1944–1946) and president (1946–1952) of the University of Texas and retired from active teaching in 1966.
Ching Chun Li
(1912–2003)
Source: Wikipedia
Ching Chun Li was a respected American population geneticist and human geneticist. Li was best known for his book An Introduction to Population Genetics and his teaching in human genetics. Ching Chun Li was born on October 27, 1912, in Taku, Tianjin, China. He received his BS degree in agronomy from the University of Nanking in 1936 and a PhD in plant breeding and genetics from Cornell University in 1940. He worked as post-doctorate fellows at Columbia University and North Carolina State University from 1940 to 1941. Li returned to China at the age of 30 and became the Professor of Genetics and Biometry at University of Nanking, his alma mater, in 1943. After World War II, he moved to Beijing for a Professorship of Agronomy at Peking University in 1946, where he finished An Introduction to Population Genetics in 1948. The book was the first notable publication where the population-genetics ideas of Ronald Fisher, Sewall Wright, and J. B. S. Haldane were brought together, synthesized, and presented in a coherent and readily understood manner.
Aravinda Chakravarti. 2004. Ching Chun Li (1912–2003):A Personal Remembrance of a Hero of Genetics The American Journal of Human Genetics, 74:789-792.
Eliot B. Spiess. 2005. Remembrance of Ching Chun Li, 1912–2003 Genetics, 169:9-11.
Erwin Chargaff
(1905–2002)
Source: Wikipedia
Erwin Chargaff (11 August 1905 – 20 June 2002) was an Austro-Hungarian biochemist that immigrated to the United States during the Nazi era and was a professor of biochemistry at Columbia University medical school. Through careful experimentation, Chargaff made two observations that helped to disprove the tetranucleotide model of DNA. Under the tetranucleotide hypothesis, it was assumed that DNA was built as a simple repeating polymer of units consisting of one adenine, one thymine, one cytosine, and one guanine. Such a structure would mean that all DNA molecules has essentially the same structure, differeing only in length. Such a molecule would be incapable of carrying hereditary information. Chargaff's observations: (1) the percent nucleotide composition of DNA was not exactly 25% of each nucleotide, (2) the percent nucleotide composition of DNA differed (slightly) from one species to another, and (3) the percent nucleotide composition of DNA was constant within a species. He also observed regular numerical patterns in the nucleotide makeup of any DNA sample. The two best remembered patterns are that, in any DNA sample, the amount of adenine always equals the amount of thymine, and the amount of guanine always equals the amount of cytosine. These observations, especially the A-T and C-G equalities, helped Watson and Crick devise the double-helix model of DNA. Chargaff had a quick wit and a sharp pen and he was not impressed with advances made through theory rather than through laboratory work. He once commented that Molecular biology is essentially the practice of biochemistry without a license.
Francis Crick
(1916–2004)
Source: Wikipedia
Francis Harry Compton Crick was a British molecular biologist, biophysicist, and neuroscientist, most noted for being a co-discoverer of the structure of the DNA molecule in 1953 with James Watson. Together with Watson and Maurice Wilkins, he was jointly awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". Crick was an important theoretical molecular biologist and played a crucial role in research related to revealing the helical structure of DNA. He is widely known for use of the term "central dogma" to summarize the idea that genetic information flow in cells is essentially one-way, from DNA to RNA to protein. During the remainder of his career, he held the post of J.W. Kieckhefer Distinguished Research Professor at the Salk Institute for Biological Studies in La Jolla, California. His later research centered on theoretical neurobiology and attempts to advance the scientific study of human consciousness. He remained in this post until his death; "he was editing a manuscript on his death bed, a scientist until the bitter end" according to Christof Koch.
James Dewey Watson
(1928– )
Source: Wikipedia
James Dewey Watsonis an American molecular biologist, geneticist and zoologist, best known as one of the co-discoverers of the structure of DNA in 1953 with Francis Crick. Watson, Crick, and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". From 1956 to 1976, Watson was on the faculty of the Harvard University Biology Department, promoting research in molecular biology. From 1968 he served as director of Cold Spring Harbor Laboratory (CSHL), greatly expanding its level of funding and research. At CSHL, he shifted his research emphasis to the study of cancer, along with making it a world leading research center in molecular biology. In 1994, he started as president and served for 10 years. He was then appointed chancellor, serving until he resigned in 2007. Between 1988 and 1992, Watson was associated with the National Institutes of Health, helping to establish the Human Genome Project.
Edmund Beecher Wilson
(1856–1939)
Source: Wikipedia
Edmund Beecher Wilson was a pioneering American zoologist and geneticist. He wrote one of the most famous textbooks in the history of modern biology, The Cell in Development and Inheritance. He and Nettie Maria Stevens were the first researchers to describe the chromosomal basis of sex, but they conducted their research independently of each other. Wilson is credited as America's first cell biologist. In 1898 he used the similarity in embryos to describe phylogenetic relationships. By observing spiral cleavage in molluscs, flatworms and annelids he concluded that the same organs came from the same group of cells and concluded that all these organisms must have a common ancestor.
Erich von Tschermak
(1864–1933)
Source: Wikipedia
Erich Tschermak, Edler von Seysenegg was an Austrian agronomist who developed several new disease-resistant crops, including wheat-rye and oat hybrids. He was a son of the Moravia-born mineralogist Gustav Tschermak von Seysenegg. His maternal grandfather was the famous botanist, Eduard Fenzl, who taught Gregor Mendel botany during his student days in Vienna.
Hugo de Vries
(1848–1935)
Source: Wikipedia
Hugo Marie de Vries was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution. In 1889, De Vries published his book Intracellular Pangenesis, in which, based on a modified version of Charles Darwin's theory of Pangenesis of 1868, he postulated that different characters have different hereditary carriers. He specifically postulated that inheritance of specific traits in organisms comes in particles. He called these units pangenes, a term 20 years later to be shortened to genes by Wilhelm Johannsen.
Ralph E. Cleland. 1936. Hugo de Vries. Proceedings of the American Philosophical Society, 76:248-250.
William Bateson
(1861–1926)
Source: Wikipedia
William Bateson was an English biologist who was the first person to use the term genetics to describe the study of heredity, and the chief populariser of the ideas of Gregor Mendel following their rediscovery in 1900 by Hugo de Vries and Carl Correns. Bateson first suggested using the word "genetics" to describe the study of inheritance and the science of variation in a personal letter to Adam Sedgwick who had been Darwin's professor), dated 18 April 1905. Bateson first used the term "genetics" publicly at the Third International Conference on Plant Hybridization in London in 1906.
Carl Correns
(1864–1933)
Source: Wikipedia
Carl Erich Correns was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendel's earlier paper on that subject, which he achieved simultaneously but independently of the botanists Erich Tschermak von Seysenegg and Hugo de Vries, and the agronomist William Jasper Spillman. Carl Correns conducted much of the foundational work for the field of genetics at the turn of the 20th century. He rediscovered and independently verified the work of Mendel in a separate model organism. He also discovered cytoplasmic inheritance, an important extension of Mendel's theories, which demonstrated the existence of extra-chromosomal factors on phenotype. Most of Correns' work went unpublished however, and was destroyed in the Berlin bombings of 1945.
Theodor Boveri
(1862–1915)
Source: Embryo Project
Theodor Heinrich Boveri was a German biologist. He was notable for first hypothesising the cellular processes that cause cancer. Boveri's work with sea urchins showed that it was necessary to have all chromosomes present in order for proper embryonic development to take place. This discovery was an important part of the Boveri–Sutton chromosome theory, which identifies chromosomes as the carriers of genetic material. The theory correctly explains the mechanism underlying the laws of Mendelian inheritance by identifying chromosomes with the paired factors (particles) required by Mendel's laws. The chromosome theory of inheritance is credited to papers by Walter Sutton in 1902 and 1903, as well as to independent work by Theodor Boveri during roughly the same period. Boveri's thoughts are summarized in his book Ergebnisse über die Konstitution der chromatischen Substanz des Zellkerns (Results on the constitution of the chromatic substance of the cell nucleus), Jena: Verlag von Gustav Fischer, 1904. His other significant discovery was the centrosome (1888), which he described as the especial organ of cell division. Boveri also discovered the phenomenon of chromatin diminution during embryonic development of the nematode Parascaris.
Clarence Erwin McClung
(1870–1946)
Source: Wikipedia
Clarence Erwin (CE) McClung was an American zoologist of wide-ranging interests. Although born in California, he spent much of his early life in Kansas. He originally studied pharmacy at Kansas University, receiving the Ph.G. degree in 1892. He taught pharmacy at the University for a year, but then his interest shifted to more general biological questions and he reenrolled as a student. From Kansas University he received the A.B. degree in 1896, the A.M. in 1898, and the Ph.D. in 1902. CE McClung made important contributions to early genetics, but he was also a general zoologist and paleontologist who received all of his degrees from Kansas and then spent his early career on the faculty there, ultimately assuming the positions of chair of the zoology department, curator of vertebrate paleontology, and even acting dean of the medical school. Early in his career, he undertook an investigation of spermatogenesis in Ziphidium fasciatum, a long-horned grasshopper. In this material he recognized that an object thought by some to be a nucleolus was actually an unpaired chromosome. Although others had noticed that this object was distributed asymmetrically into some but not all spermatozoa, McClung was the first to see that this could provide a cytological mechanism of sex determination.
D. H. Wenrich. 1946. Clarence Erwin McClung 1870-1946 Science, 103:551-552. DOI: 10.1126/science.103.2679.551
David Henry Wenrich Papers: A collection largely developed to support the Dr. Wenrich's efforts to honor Dr. Clarence Erwin McClung.
Archibald Garrod
(1857–1938)
Source: Wikipedia
Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. He also discovered alkaptonuria, understanding its inheritance. He served as Regius Professor of Medicine at the University of Oxford from 1920 to 1927. Garrod is best known for his scientific study of inborn errors of metabolism. He developed an increasing interest in chemical pathology, and investigated urine chemistry as a reflection of systemic metabolism and disease. This research, combined with the new understanding of Mendelian inheritance, evolved from an investigation of a few families with an obscure and not very dangerous disease (alkaptonuria) to the realization that a whole territory of mysterious diseases might be understood as inherited disorders of metabolism. Working with William Bateson, Garrod came to understand the pattern of alkaptonuria appearance in children based on Mendelian principles. Once he applied Mendel’s concepts to alkaptonuria, he published a paper in 1902 called The Incidence of Alkaptonuria: A Study of Chemical Individuality. In the paper, Garrod explains how he came to understand the condition and speculates as to its causes. He cites various case studies and compares alkaptonuria to albinism in how it is inherited. He summarized his thoughts on the relationship of inheritance to metabolic disease in his book Inborn Errors of Metabolism .
F. G. Hopkins. 1938. Archibald Edward Garrod. 1857–1936. Biographical Memoirs of fellows of the Royal Society, 2:225–228.
Krishna Dronamraju. 1992. BIOGRAPHY Profiles in Genetics: Archibald E. Garrod (1857-1936). american Journal of Human Genetics, 51:216-219.
Nettie Marie Stevens
(1861–1912)
Source: Wikipedia
Nettie Maria Stevens was an early American geneticist. In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system.
Reginald Crundall Punnett
(1875–1967)
Source: Wikipedia
Reginald Crundall Punnett was a British geneticist who co-founded, with William Bateson, the Journal of Genetics in 1910. Punnett is probably best remembered today as the creator of the Punnett square, a tool still used by biologists to predict the probability of possible genotypes of offspring. His little book (62 small pages) Mendelism (1905) is sometimes said to have been the first textbook on genetics; it was probably the first popular science book to introduce genetics to the public.
Wilhelm Weinberg
(1862–1937)
Source: Wikipedia
Dr Wilhelm Weinberg was a German obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper, published in German in Jahresheft des Vereins für vaterländische Naturkunde in Württemberg (The Annals of the Society of National Natural History in Württemberg), expressed the concept that would later come to be known as the Hardy-Weinberg principle. Weinberg is also credited as the first to explain the effect of ascertainment bias on observations in genetics. Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the Verein für vaterländische Naturkunde in Württemberg (Society for the Natural History of the Fatherland in Württemberg), about six months before Hardy's paper was published in English. His lecture was printed later that year in the society's yearbook. Weinberg's contributions were unrecognized in the English speaking world for more than 35 years. Curt Stern, a German scientist who immigrated to the United States before World War II, pointed out in a brief paper in Science that Weinberg's exposition was both earlier and more comprehensive than Hardy's. Before 1943, the concepts in genetic equilibrium that are known today as the Hardy-Weinberg principle had been known as "Hardy's law" or "Hardy's formula" in English-language texts.
Godfrey Harold Hardy
(1877–1947)
Source: Wikipedia
Godfrey Harold "G. H." Hardy was an English mathematician, known for his achievements in number theory and mathematical analysis. In addition to his research, Hardy is remembered for his 1940 essay on the aesthetics of mathematics, entitled A Mathematician's Apology. He was the mentor of the Indian mathematician Srinivasa Ramanujan. Although every geneticist has heard of the Hardy-Weinberg Law and of Hardy-Weinberg Equilibrium, and although nearly all basic biology texts teach that G. H. Hardy played a seminal role in founding population genetics, most biologists don't realize that Hardy's total contribution to biology consisted of a single one-page letter to the editor in Science. The letter began, I am reluctant to intrude in a discussion concerning matters of which I have no expert knowledge, and I should have expected the very simple point which I wish to make to have been familiar to biologists. However, some remarks of Mr. Udny Yule, to which Mr. R. C. Punnett has called my attention, suggest that it may still be worth making. With that, Hardy offered his "simple point" and then washed his hands of biology. His autobiography, A Mathematician's Apology, makes no mention of population genetics. Mathematically, Hardy's "very simple point" was the trivial assertion that (p + q)2 = p2 + 2pq + q2 Biologically, however, Hardy's point was of greater consequence, as his simple algebra implied that Mendelian mechanisms, acting alone, have no effect upon allele frequencies in a population — an observation that was far from obvious to most biologists.
Hermann Joseph Muller
(1890–1967)
Source: Wikipedia
Hermann Joseph Muller (or H. J. Muller) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (Mutagenesis) as well as his outspoken political beliefs. Muller frequently warned of the long-term dangers of radioactive fallout from nuclear war and nuclear testing, helping to raise public awareness in this area. At 16 he entered Columbia College. From his first semester he was interested in biology; he became an early convert of the Mendelian-chromosome theory of heredity — and the concept of genetic mutations and natural selection as the basis for evolution. Muller remained at Columbia (the pre-eminent American zoology program at the time, thanks to E. B. Wilson and his students) for graduate school. He became interested in the Drosophila genetics work of Thomas Hunt Morgan's fly lab after undergraduate bottle washers Alfred Sturtevant and Calvin Bridges joined his Biology Club. He joined Morgan's group in 1912 (after two years of informal participation). In 1918, he proposed an explanation for the dramatic discontinuous alterations in Oenothera larmarckiana that were the basis of Hugo de Vries's theory of mutationism: "balanced lethals" allowed the accumulation of recessive mutations, and rare crossing over events resulted in the sudden expression of these hidden traits. In other words, de Vries's experiments were explainable by the Mendelian-chromosome theory.
Alfred Henry Sturtevant
(1891–1970)
Source: Wikipedia
Alfred Henry Sturtevant was an American geneticist. While still a student, Sturtevant constructed the first genetic map of a chromosome in 1913. Throughout his career he worked on the organism Drosophila melanogaster with Thomas Hunt Morgan. By watching the development of flies in which the earliest cell division produced two different genomes, he measured the embryonic distance between organs in a unit which is called the sturt in his honor. In 1965, Sturtevant published a first-rate, first-person account of A History of Genetics.
Edward B. Lewis. Alfred Henry Sturtevant November 21, 1891 – April 5, 1970. Biographical Memoirs of the National Academy of Science, 73:348–362.
Guide to the Alfred H. Sturtevant Papers, 1849-1969. Online Archive of California.
Calvin Blackman Bridges
(1889–1938)
Source: Wikipedia
Calvin Blackman Bridges was born in Schuyler Falls, New York in 1889 to the parents of Leonard Bridges and Charlotte Blackman. Tragically, Calvin's mother died when he was two years old, and his father died a year after his mother's death, leaving Calvin Bridges an orphan. Following the death of his parents, Bridges was taken in and raised by his grandmother. Despite now being known in the scientific world as one of the most influential researchers regarding Drosophila melanogaster, it took Bridges several years to complete high school, graduating when he was 20 years old. However, despite this setback, Bridges moved on to be an outstanding student at Columbia University, which he attended both for undergraduate and postgraduate school. While taking a zoology class, Bridges met Thomas Hunt Morgan. This started a relationship which would lead to many important discoveries in the scientific world regarding genetics and evolution. Bridges wrote a masterful Ph.D. thesis on Non-disjunction as proof of the chromosome theory of heredity (click HERE for part 2 ) which appeared as the first paper in the first issue of the journal Genetics in 1916. In this paper, he also established that the Y-chromosome does not determine gender in Drosophila.
Thomas Hunt Morgan
(1866–1945)
Source: Wikipedia
Thomas Hunt Morgan was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, Drosophila became a major model organism in contemporary genetics. The Division of Biology which he established at the California Institute of Technology has produced seven Nobel Prize winners.
Garland E. Allen. 1979. Thomas Hunt Morgan: The Man and His Science. Princeton: Princeton University Press. 447 pp. (The definitive biography)
Robert E. Kohler. 1994. Lords of the Fly: Drosophila Genetics and the Experimental Life. Chicago: University of Chicago Press. 344pp. (An excellent treatment of the early work in Drosophila genetics)
H. J. Muller. 1946. Thomas Hunt Morgan 1866–1945. Science, 103:550–551.
Diana E. Kenney and Gary G. Borisy. 2009. Thomas Hunt Morgan at the Marine Biological Laboratory: Naturalist and Experimentalist. Genetics, 181:841-846.
R. A. Fisher and G. R. de Beer. 1947. Thomas Hunt Morgan. 1866–1945. Obituary Notices of Fellows of the Royal Society, 5:451-466.
Stephen G. Brush. 2002. How Theories became Knowledge: Morgan's Chromosome Theory of Heredity in America and Britain. Journal of the History of Biology, 35:471–535.
Norman H. Horowitz. 1998. T. H. Morgan at Caltech: A Reminiscence. Genetics, 149:1629–1632.
John Burton Sanderson Haldane
(1892–1964)
Source: Wikipedia
John Burdon Sanderson Haldane was a British-born scientist known for his work in the study of physiology, genetics, evolutionary biology, and in mathematics, where he made innovative contributions to the fields of statistics and biostatistics. He was the son of the equally famous John Scott Haldane and was a professed socialist, Marxist, atheist, and humanist whose political dissent led him to leave England in 1956 and live in India, becoming a naturalised Indian citizen in 1961. His first paper in 1915 demonstrated genetic linkage in mammals while subsequent works helped to create population genetics, thus establishing a unification of Mendelian genetics and Darwinian evolution by natural selection whilst laying the groundwork for modern evolutionary synthesis. He was one of the three major figures to develop the mathematical theory of population genetics, along with Ronald Fisher and Sewall Wright. Thusly he played an important role in the modern evolutionary synthesis, which is popularly called "neo-Darwinism", as in Richard Dawkins' 1976 work titled The Selfish Gene. He re-established natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian inheritance. He wrote a series of ten papers called A Mathematical Theory of Natural and Artificial Selection, on the numerical formalism underpinning natural selection. It showed that gene frequencies have direction and rates of change; and he pioneered the interaction of natural selection with mutation and animal migration. Haldane's book, The Causes of Evolution (1932), summarised these results, especially in its extensive appendix. Arthur C. Clarke credited him as "perhaps the most brilliant science populariser of his generation". Nobel laureate Peter Medawar called Haldane "the cleverest man I ever knew".
Ronald Aylmer Fisher
(1890–1962)
Source: Wikipedia
Sir Ronald Aylmer Fisher, who published as R. A. Fisher, was an English statistician and biologist who used mathematics to combine Mendelian genetics and natural selection. This contributed to the revival of Darwinism in the early 20th century revision of the theory of evolution known as the modern synthesis. He was a prominent eugenicist in the early part of his life. In 1918 he published The Correlation Between Relatives on the Supposition of Mendelian Inheritance in 1918, in which he simultaneously resolved one of the outstanding debates in biology (the biometricians vs. the Mendelians) and introduced the idea of the analysis of variance. This paper was originally submitted to Biometrika where it was rejected, with a biological reviewer allowing that perhaps the mathematics had some value, but the biology was inconsequential while a statistical reviewer held the converse view. In 1925 he published Statistical Methods for Research Workers, one of the 20th century's most influential books on statistical methods. Fisher's method is a technique for data fusion or "meta-analysis" (analysis of analyses). This book also popularized the p-value, and it plays a central role in his approach. Fisher proposes the level p = 0.05, or a 1 in 20 chance of being exceeded by chance, as a limit for statistical significance, and applies this to a normal distribution (as a two-tailed test), thus yielding the rule of two standard deviations (on a normal distribution) for statistical significance. In 1933 he became Professor of Eugenics at University College London until 1939 when the department was dissolved. In 1935, he published by The Design of Experiments, which was also fundamental, [and promoted] statistical technique and application. In this book Fisher also outlined the Lady tasting tea, now a famous design of a statistical randomized experiment which uses Fisher's exact test and is the original exposition of Fisher's notion of a null hypothesis. In 1936 he published Has Mendel's Work Been Rediscovered?, in which he suggested that Mendel's results were too good to be true and that someone (perhaps an over-eager assistant) had fudged the results.
Sewall Wright
(1889–1988)
Source: Wikipedia
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. He was a founder of population genetics alongside Ronald Fisher and J.B.S. Haldane, which was a major step in the development of the modern evolutionary synthesis combining genetics with evolution. He discovered the inbreeding coefficient and methods of computing it in pedigree animals. He extended this work to populations, computing the amount of inbreeding between members of populations as a result of random genetic drift, and along with Fisher he pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. Wright also made major contributions to mammalian and biochemical genetics. His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. In this work he also introduced the concept of effective population size. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or evolutionary landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.
Theophilus S. Painter
(1889–1969)
Source: Wikipedia
Theophilus Shickel Painter was an American zoologist best-known for his work on the structure and function of chromosomes, especially the sex-determination genes X and Y in humans. He also carried out work in identifying genes in fruit flies (Drosophila). His work exploited the giant polytene chromosomes in the salivary glands of Drosophila and other Dipteran larvae. Painter joined the faculty at the University of Texas in 1916 and, except for military duty during World War I, stayed there his whole career. He was, in succession, associate professor, professor and distinguished professor of zoology. He served as acting president (1944–1946) and president (1946–1952) of the University of Texas and retired from active teaching in 1966.
Ching Chun Li
(1912–2003)
Source: Wikipedia
Ching Chun Li was a respected American population geneticist and human geneticist. Li was best known for his book An Introduction to Population Genetics and his teaching in human genetics. Ching Chun Li was born on October 27, 1912, in Taku, Tianjin, China. He received his BS degree in agronomy from the University of Nanking in 1936 and a PhD in plant breeding and genetics from Cornell University in 1940. He worked as post-doctorate fellows at Columbia University and North Carolina State University from 1940 to 1941. Li returned to China at the age of 30 and became the Professor of Genetics and Biometry at University of Nanking, his alma mater, in 1943. After World War II, he moved to Beijing for a Professorship of Agronomy at Peking University in 1946, where he finished An Introduction to Population Genetics in 1948. The book was the first notable publication where the population-genetics ideas of Ronald Fisher, Sewall Wright, and J. B. S. Haldane were brought together, synthesized, and presented in a coherent and readily understood manner.
Aravinda Chakravarti. 2004. Ching Chun Li (1912–2003):A Personal Remembrance of a Hero of Genetics The American Journal of Human Genetics, 74:789-792.
Eliot B. Spiess. 2005. Remembrance of Ching Chun Li, 1912–2003 Genetics, 169:9-11.
Theodor Schwann
(1810–1882)
Source: Wikipedia
Theodor Schwann was a German physiologist. His many contributions to biology include the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the organic nature of yeast, and the invention of the term metabolism. In 1837, Matthias Jakob Schleiden viewed and stated that new plant cells formed from the nuclei of old plant cells. While dining that year with Schwann, the conversation turned on the nuclei of plant and animal cells. Schwann remembered seeing similar structures in the cells of the notochord (as had been shown by Müller) and instantly realized the importance of connecting the two phenomena. The resemblance was confirmed without delay by both observers, and the results soon appeared in Schwann's famous Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants, in which he declared that "All living things are composed of cells and cell products". This became cell theory or cell doctrine. In the course of his verification of cell theory, Schwann proved the cellular origin and development of the most highly differentiated tissues including nails, feathers, and tooth enamel. Schwann established a basic principle of embryology by observing that the ovum is a single cell that eventually develops into a complete organism.
Matthias Jakob Schleiden
(1804–1881)
Source: Wikipedia
Matthias Jakob Schleiden was a German botanist and co-founder of cell theory, along with Theodor Schwann and Rudolf Virchow. Born in Hamburg, Schleiden was educated at University of Jena, then practiced law in Heidelberg, but soon developed his love for botany into a full-time pursuit. Schleiden preferred to study plant structure under the microscope. While a professor of botany at the University of Jena, he wrote Contributions to our knowledge of phytogenesis (1838), in which he stated that all parts of the plant organism are composed of cells. Thus, Schleiden and Schwann became the first to formulate what was then an informal belief as a principle of biology equal in importance to the atomic theory of chemistry. He also recognized the importance of the cell nucleus, discovered in 1831 by the Scottish botanist Robert Brown, and sensed its connection with cell division. Schleiden was one of the first German biologists to accept Charles Darwin's theory of evolution. He became professor of botany at the University of Dorpat in 1863. He concluded that all plant parts are made of cells and that an embryonic plant organism arises from the one cell.
Rudolf Virchow
(1821–1902)
Source: Wikipedia
Rudolf Ludwig Carl Virchow was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician, known for his advancement of public health. He is known as "the father of modern pathology" because his work helped to discredit humourism, bringing more science to medicine. He is also known as the founder of social medicine and veterinary pathology, and to his colleagues, the "Pope of medicine". A prolific writer, his scientific writings alone exceeded 2,000 in number. Among his books, Cellular Pathology published in 1858 is regarded as the root of modern pathology. This work also popularised the third dictum in cell theory: Omnis cellula e cellula ("All cells come from cells"); although his idea originated in 1855. Virchow is credited with several very important discoveries. His most widely known scientific contribution is his cell theory, which built on the work of Theodor Schwann. He was one of the first to accept the work of Robert Remak, who showed the origins of cells was the division of pre-existing cells. He did not initially accept the evidence for cell division, believing it only occurs in certain types of cells. When it dawned on him that Remak might be right, in 1855, he published Remak's work as his own, which caused a falling out between the two. This work, Virchow encapsulated in the epigram Omnis cellula e cellula ("all cells (come) from cells"), which he published in 1855. He was an ardent anti-evolutionist. He referred to Charles Darwin as an "ignoramus" and his own student Ernst Haeckel, the leading advocate of Darwinism in Germany, as a "fool". He discredited the original specimen of Neanderthal man as nothing but that of a deformed human, and not an ancestral species.
Eduard Strasburger
(1844–1912)
Source: Wikipedia
Eduard Adolf Strasburger was a Polish-German professor who was one of the most famous botanists of the 19th century. Strasburger studied biological sciences in Paris, Bonn and Jena, receiving a PhD in 1866 after working with Nathanael Pringsheim. In 1868 he taught at the University of Warsaw. In 1869 he was appointed professor of botany at the University of Jena. Since 1881 he was head of the Botanisches Institut at the University of Bonn. Together with Walther Flemming, and Edouard van Beneden he elucidated chromosome distribution during cell division.
Walther Flemming
(1843–1905)
Source: Wikipedia
Walther Flemming was a German biologist and a founder of cytogenetics. Flemming trained in medicine at University of Rostock, graduating in 1868. Afterwards, he served in 1870–71 as a military physician in the Franco-Prussian War. From 1873 to 1876 he worked as a teacher at the University of Prague. In 1876 he accepted a post as a professor of anatomy at the University of Kiel. He became the director of the Anatomical Institute and stayed there until his death. With the use of aniline dyes he was able to find a structure which strongly absorbed basophilic dyes, which he named chromatin. He identified that chromatin was correlated to threadlike structures in the cell nucleus – the chromosomes (meaning coloured bodies), which were named thus later by German anatomist Wilhelm von Waldeyer-Hartz (1841–1923). The Belgian scientist Edouard Van Beneden (1846–1910) had also independently observed chromosomes. Flemming investigated the process of cell division and the distribution of chromosomes to the daughter nuclei, a process he called mitosis from the Greek word for thread. However, he did not see the splitting into identical halves, the daughter chromatids. He studied mitosis both in vivo and in stained preparations, using as the source of biological material the fins and gills of salamanders. These results were published first in 1878 and in 1882 in the seminal book Zellsubstanz, Kern und Zelltheilung (Cell substance, nucleus and cell division). On the basis of his discoveries, Flemming surmised for the first time that all cell nuclei came from another predecessor nucleus (he coined the phrase omnis nucleus e nucleo, after Virchow's omnis cellula e cellula).
Neidhard Paweletz. 2001. Walther Flemming: pioneer of mitosis research. Nature Reviews Molecular Cell Biology, 2:72-75. | doi:10.1038/35048077
Édouard Joseph Louis Marie van Beneden
(1846–1910)
Source: Wikipedia
Édouard Joseph Louis Marie Van Beneden was a Belgian embryologist, cytologist and marine biologist. He was professor of zoology at the University of Liège. He contributed to cytogenetics by his works on the roundworm Ascaris. In this work he discovered and described the process of meiosis — a two-cell-division process by which cells reduce the number of chromosomes in preparation for the production of gametes. Van Beneden also elucidated, together with Walther Flemming and Eduard Strasburger, the essential facts of mitosis — the single-cell-division process that distributes equal chromosome complements to each of the two daughter cells.
Heinrich Wilhelm Gottfried von Waldeyer-Hartz
(1836–1921)
Source: Wikipedia
Heinrich Wilhelm Gottfried von Waldeyer-Hartz was a German anatomist, famous for consolidating the neuron theory of organization of the nervous system and for naming the chromosome. He is also remembered in two macroanatomical structures of the human body which were named after him: Waldeyer's tonsillar ring (the lymphoid tissue ring of the naso- and oropharynx) and Waldeyer's glands (of the eyelids). Waldeyer also studied the basophilic stained filaments which had been found (by his colleague of Kiel, Walther Flemming) to be the main constituents of chromatin, the material inside the cell nucleus. Although the full significance of chromosomes for genetics and for cell biology was still to be discovered, these filaments were known to be involved in the phenomenon of cell division discovered by Flemming, named mitosis, as well as in meiosis. In 1888, Waldeyer coined the term chromosome — colored body — to describe them.
T. Cremer and C. Cremer. 1988. Centennial of Wilhelm Waldeyer’s introduction of the term “chromosome” in 1888. Cytogenetics and Cell Genetics, 48:66–67. (DOI:10.1159/000132591)
Waldeyer's 1888 paper in which he uses the word chromosome: Über Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen.
August Weismann
(1834–1914)
Source: Wikipedia
August Friedrich Leopold Weismann was a German evolutionary biologist. Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg. His main contribution involved his Germ Plasm Theory, at one time also known as Weismannism, according to which inheritance (in a multicellular organism) only takes place by means of the germ cells — the gametes such as egg cells and sperm cells. Other cells of the body — somatic cells — do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck. The idea of the Weismann barrier is central to the modern evolutionary synthesis, though scholars do not express it today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann became one of the first biologists to deny Lamarckism entirely. Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection. Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–1940, and "one of the great biologists of all time".
Essays Upon Heredity — a collection of Weismann's writing on hereditary issues.
Yawen Zou. 2015. The Germ-Plasm: a Theory of Heredity (1893), by August Weismann. The Embryo Project Encyclopedia.
Edwin G. Conklin. 1915. August Weismann. Proceedings of the American Philosophical Society, 54:3-12.
Edmund Beecher Wilson
(1856–1939)
Source: Wikipedia
Edmund Beecher Wilson was a pioneering American zoologist and geneticist. He wrote one of the most famous textbooks in the history of modern biology, The Cell in Development and Inheritance. He and Nettie Maria Stevens were the first researchers to describe the chromosomal basis of sex, but they conducted their research independently of each other. Wilson is credited as America's first cell biologist. In 1898 he used the similarity in embryos to describe phylogenetic relationships. By observing spiral cleavage in molluscs, flatworms and annelids he concluded that the same organs came from the same group of cells and concluded that all these organisms must have a common ancestor.
Theodor Boveri
(1862–1915)
Source: Embryo Project
Theodor Heinrich Boveri was a German biologist. He was notable for first hypothesising the cellular processes that cause cancer. Boveri's work with sea urchins showed that it was necessary to have all chromosomes present in order for proper embryonic development to take place. This discovery was an important part of the Boveri–Sutton chromosome theory, which identifies chromosomes as the carriers of genetic material. The theory correctly explains the mechanism underlying the laws of Mendelian inheritance by identifying chromosomes with the paired factors (particles) required by Mendel's laws. The chromosome theory of inheritance is credited to papers by Walter Sutton in 1902 and 1903, as well as to independent work by Theodor Boveri during roughly the same period. Boveri's thoughts are summarized in his book Ergebnisse über die Konstitution der chromatischen Substanz des Zellkerns (Results on the constitution of the chromatic substance of the cell nucleus), Jena: Verlag von Gustav Fischer, 1904. His other significant discovery was the centrosome (1888), which he described as the especial organ of cell division. Boveri also discovered the phenomenon of chromatin diminution during embryonic development of the nematode Parascaris.
Clarence Erwin McClung
(1870–1946)
Source: Wikipedia
Clarence Erwin (CE) McClung was an American zoologist of wide-ranging interests. Although born in California, he spent much of his early life in Kansas. He originally studied pharmacy at Kansas University, receiving the Ph.G. degree in 1892. He taught pharmacy at the University for a year, but then his interest shifted to more general biological questions and he reenrolled as a student. From Kansas University he received the A.B. degree in 1896, the A.M. in 1898, and the Ph.D. in 1902. CE McClung made important contributions to early genetics, but he was also a general zoologist and paleontologist who received all of his degrees from Kansas and then spent his early career on the faculty there, ultimately assuming the positions of chair of the zoology department, curator of vertebrate paleontology, and even acting dean of the medical school. Early in his career, he undertook an investigation of spermatogenesis in Ziphidium fasciatum, a long-horned grasshopper. In this material he recognized that an object thought by some to be a nucleolus was actually an unpaired chromosome. Although others had noticed that this object was distributed asymmetrically into some but not all spermatozoa, McClung was the first to see that this could provide a cytological mechanism of sex determination.
D. H. Wenrich. 1946. Clarence Erwin McClung 1870-1946 Science, 103:551-552. DOI: 10.1126/science.103.2679.551
David Henry Wenrich Papers: A collection largely developed to support the Dr. Wenrich's efforts to honor Dr. Clarence Erwin McClung.
Nettie Marie Stevens
(1861–1912)
Source: Wikipedia
Nettie Maria Stevens was an early American geneticist. In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system.
Theophilus S. Painter
(1889–1969)
Source: Wikipedia
Theophilus Shickel Painter was an American zoologist best-known for his work on the structure and function of chromosomes, especially the sex-determination genes X and Y in humans. He also carried out work in identifying genes in fruit flies (Drosophila). His work exploited the giant polytene chromosomes in the salivary glands of Drosophila and other Dipteran larvae. Painter joined the faculty at the University of Texas in 1916 and, except for military duty during World War I, stayed there his whole career. He was, in succession, associate professor, professor and distinguished professor of zoology. He served as acting president (1944–1946) and president (1946–1952) of the University of Texas and retired from active teaching in 1966.
Wilhelm Weinberg
(1862–1937)
Source: Wikipedia
Dr Wilhelm Weinberg was a German obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper, published in German in Jahresheft des Vereins für vaterländische Naturkunde in Württemberg (The Annals of the Society of National Natural History in Württemberg), expressed the concept that would later come to be known as the Hardy-Weinberg principle. Weinberg is also credited as the first to explain the effect of ascertainment bias on observations in genetics. Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the Verein für vaterländische Naturkunde in Württemberg (Society for the Natural History of the Fatherland in Württemberg), about six months before Hardy's paper was published in English. His lecture was printed later that year in the society's yearbook. Weinberg's contributions were unrecognized in the English speaking world for more than 35 years. Curt Stern, a German scientist who immigrated to the United States before World War II, pointed out in a brief paper in Science that Weinberg's exposition was both earlier and more comprehensive than Hardy's. Before 1943, the concepts in genetic equilibrium that are known today as the Hardy-Weinberg principle had been known as "Hardy's law" or "Hardy's formula" in English-language texts.
Godfrey Harold Hardy
(1877–1947)
Source: Wikipedia
Godfrey Harold "G. H." Hardy was an English mathematician, known for his achievements in number theory and mathematical analysis. In addition to his research, Hardy is remembered for his 1940 essay on the aesthetics of mathematics, entitled A Mathematician's Apology. He was the mentor of the Indian mathematician Srinivasa Ramanujan. Although every geneticist has heard of the Hardy-Weinberg Law and of Hardy-Weinberg Equilibrium, and although nearly all basic biology texts teach that G. H. Hardy played a seminal role in founding population genetics, most biologists don't realize that Hardy's total contribution to biology consisted of a single one-page letter to the editor in Science. The letter began, I am reluctant to intrude in a discussion concerning matters of which I have no expert knowledge, and I should have expected the very simple point which I wish to make to have been familiar to biologists. However, some remarks of Mr. Udny Yule, to which Mr. R. C. Punnett has called my attention, suggest that it may still be worth making. With that, Hardy offered his "simple point" and then washed his hands of biology. His autobiography, A Mathematician's Apology, makes no mention of population genetics. Mathematically, Hardy's "very simple point" was the trivial assertion that (p + q)2 = p2 + 2pq + q2 Biologically, however, Hardy's point was of greater consequence, as his simple algebra implied that Mendelian mechanisms, acting alone, have no effect upon allele frequencies in a population — an observation that was far from obvious to most biologists.
John Burton Sanderson Haldane
(1892–1964)
Source: Wikipedia
John Burdon Sanderson Haldane was a British-born scientist known for his work in the study of physiology, genetics, evolutionary biology, and in mathematics, where he made innovative contributions to the fields of statistics and biostatistics. He was the son of the equally famous John Scott Haldane and was a professed socialist, Marxist, atheist, and humanist whose political dissent led him to leave England in 1956 and live in India, becoming a naturalised Indian citizen in 1961. His first paper in 1915 demonstrated genetic linkage in mammals while subsequent works helped to create population genetics, thus establishing a unification of Mendelian genetics and Darwinian evolution by natural selection whilst laying the groundwork for modern evolutionary synthesis. He was one of the three major figures to develop the mathematical theory of population genetics, along with Ronald Fisher and Sewall Wright. Thusly he played an important role in the modern evolutionary synthesis, which is popularly called "neo-Darwinism", as in Richard Dawkins' 1976 work titled The Selfish Gene. He re-established natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian inheritance. He wrote a series of ten papers called A Mathematical Theory of Natural and Artificial Selection, on the numerical formalism underpinning natural selection. It showed that gene frequencies have direction and rates of change; and he pioneered the interaction of natural selection with mutation and animal migration. Haldane's book, The Causes of Evolution (1932), summarised these results, especially in its extensive appendix. Arthur C. Clarke credited him as "perhaps the most brilliant science populariser of his generation". Nobel laureate Peter Medawar called Haldane "the cleverest man I ever knew".
Ronald Aylmer Fisher
(1890–1962)
Source: Wikipedia
Sir Ronald Aylmer Fisher, who published as R. A. Fisher, was an English statistician and biologist who used mathematics to combine Mendelian genetics and natural selection. This contributed to the revival of Darwinism in the early 20th century revision of the theory of evolution known as the modern synthesis. He was a prominent eugenicist in the early part of his life. In 1918 he published The Correlation Between Relatives on the Supposition of Mendelian Inheritance in 1918, in which he simultaneously resolved one of the outstanding debates in biology (the biometricians vs. the Mendelians) and introduced the idea of the analysis of variance. This paper was originally submitted to Biometrika where it was rejected, with a biological reviewer allowing that perhaps the mathematics had some value, but the biology was inconsequential while a statistical reviewer held the converse view. In 1925 he published Statistical Methods for Research Workers, one of the 20th century's most influential books on statistical methods. Fisher's method is a technique for data fusion or "meta-analysis" (analysis of analyses). This book also popularized the p-value, and it plays a central role in his approach. Fisher proposes the level p = 0.05, or a 1 in 20 chance of being exceeded by chance, as a limit for statistical significance, and applies this to a normal distribution (as a two-tailed test), thus yielding the rule of two standard deviations (on a normal distribution) for statistical significance. In 1933 he became Professor of Eugenics at University College London until 1939 when the department was dissolved. In 1935, he published by The Design of Experiments, which was also fundamental, [and promoted] statistical technique and application. In this book Fisher also outlined the Lady tasting tea, now a famous design of a statistical randomized experiment which uses Fisher's exact test and is the original exposition of Fisher's notion of a null hypothesis. In 1936 he published Has Mendel's Work Been Rediscovered?, in which he suggested that Mendel's results were too good to be true and that someone (perhaps an over-eager assistant) had fudged the results.
Sewall Wright
(1889–1988)
Source: Wikipedia
Sewall Green Wright was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. He was a founder of population genetics alongside Ronald Fisher and J.B.S. Haldane, which was a major step in the development of the modern evolutionary synthesis combining genetics with evolution. He discovered the inbreeding coefficient and methods of computing it in pedigree animals. He extended this work to populations, computing the amount of inbreeding between members of populations as a result of random genetic drift, and along with Fisher he pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. Wright also made major contributions to mammalian and biochemical genetics. His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. In this work he also introduced the concept of effective population size. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or evolutionary landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.
Ching Chun Li
(1912–2003)
Source: Wikipedia
Ching Chun Li was a respected American population geneticist and human geneticist. Li was best known for his book An Introduction to Population Genetics and his teaching in human genetics. Ching Chun Li was born on October 27, 1912, in Taku, Tianjin, China. He received his BS degree in agronomy from the University of Nanking in 1936 and a PhD in plant breeding and genetics from Cornell University in 1940. He worked as post-doctorate fellows at Columbia University and North Carolina State University from 1940 to 1941. Li returned to China at the age of 30 and became the Professor of Genetics and Biometry at University of Nanking, his alma mater, in 1943. After World War II, he moved to Beijing for a Professorship of Agronomy at Peking University in 1946, where he finished An Introduction to Population Genetics in 1948. The book was the first notable publication where the population-genetics ideas of Ronald Fisher, Sewall Wright, and J. B. S. Haldane were brought together, synthesized, and presented in a coherent and readily understood manner.
Aravinda Chakravarti. 2004. Ching Chun Li (1912–2003):A Personal Remembrance of a Hero of Genetics The American Journal of Human Genetics, 74:789-792.
Eliot B. Spiess. 2005. Remembrance of Ching Chun Li, 1912–2003 Genetics, 169:9-11.
Thomas Robert Malthus
(1766–1834)
Source: Wikipedia
Thomas Robert Malthus was an English cleric and scholar, influential in the fields of political economy and demography. Malthus himself used only his middle name, Robert. In his book An Essay on the Principle of Population, Malthus observed that an increase in a nation's food production improved the well-being of the populace, but the improvement was temporary because it led to population growth, which in turn restored the original per capita production level. In other words, mankind had a propensity to utilize abundance for population growth rather than for maintaining a high standard of living, a view that has become known as the "Malthusian trap" or the "Malthusian spectre". Populations had a tendency to grow until the lower class suffered hardship and want and greater susceptibility to famine and disease, a view that is sometimes referred to as a Malthusian catastrophe. Malthus wrote in opposition to the popular view in 18th-century Europe that saw society as improving and in principle as perfectible. He saw population growth as being inevitable whenever conditions improved, thereby precluding real progress towards a utopian society: "The power of population is indefinitely greater than the power in the earth to produce subsistence for man". His views became influential, and controversial, across economic, political, social and scientific thought. Pioneers of evolutionary biology read him, notably Charles Darwin and Alfred Russel Wallace.
Charles Darwin
(1809–1882)
Source: Wikipedia
Charles Robert Darwin was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. He established that all species of life have descended over time from common ancestors and, in a joint publication with Alfred Russel Wallace, introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s, the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.
Darwin Online: The world's largest and most widely used resource on Darwin, containing his complete publications, his private papers and manuscripts, and much supplementary material.
Alfred Russel Wallace
(1823–1913)
Source: Wikipedia
Alfred Russel Wallace was a British naturalist, explorer, geographer, anthropologist, and biologist. He is best known for independently conceiving the theory of evolution through natural selection; his paper on the subject was jointly published with some of Charles Darwin's writings in 1858. This prompted Darwin to publish his own ideas in On the Origin of Species. Wallace did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the animals are largely of Asian origin, and an eastern portion where the fauna reflect Australasia. He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography". Wallace was one of the leading evolutionary thinkers of the 19th century and made many other contributions to the development of evolutionary theory besides being co-discoverer of natural selection. These included the concept of warning colouration in animals, and the Wallace effect, a hypothesis on how natural selection could contribute to speciation by encouraging the development of barriers against hybridisation. Wallace was strongly attracted to unconventional ideas (such as evolution). His advocacy of spiritualism and his belief in a non-material origin for the higher mental faculties of humans strained his relationship with some members of the scientific establishment.
The Alfred Russel Wallace Website
Encyclopædia Britannica: Alfred Russel Wallace
The Alfred Russel Wallace Page
The New Yorker: Missing Link, Alfred Russel Wallace, Charles Darwin’s neglected double.
NOVA: Great Minds Think Alike, How Alfred Wallace Came to Share Darwin's Revolutionary Insight
Wallace Online (the first complete edition of the writings of Alfred Russel Wallace, including the first compilation of his specimens)
Alfred Russel Wallace, Darwin Correspondence Project
William Keith Brooks
(1848–1908)
Source: Wikipedia
William Keith Brooks received a Bachelor of Arts degree from Williams College in 1870 and a PhD from Harvard in 1875. With the opening of The Johns Hopkins University in 1876, Brooks received one of the university's initial fellowships and he quickly advanced within the organization, ultimately serving as Professor of Zoology and Head of the Biological Department. At the young age of 36 he was elected a member of the National Academy. He was chosen as a member of the American Philosophical Society in 1886 and of the Academy of Natural Science in 1887. Although many of Brooks' scientific contributions represent solid, nineteeth-century work, his most lasting effect came from his long-standing conviction that the processes of heredity were themselves a proper subject of investigation. In 1876 he wrote a paper entitled "A Provisional Hypothesis of Pangenesis" and he gave the subject a book-length treatment in his The Law of Heredity. A Study of the Cause of Variation and the Origin of Living Organisms. He was known as both a man of deep, abstract thought and an excellent teacher, as evidenced by the fact that many of the still well-known pioneers of genetics had, at one time or another, studied with him: viz. Thomas Morgan, E. B. Wilson, and William Bateson.
August Weismann
(1834–1914)
Source: Wikipedia
August Friedrich Leopold Weismann was a German evolutionary biologist. Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg. His main contribution involved his Germ Plasm Theory, at one time also known as Weismannism, according to which inheritance (in a multicellular organism) only takes place by means of the germ cells — the gametes such as egg cells and sperm cells. Other cells of the body — somatic cells — do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck. The idea of the Weismann barrier is central to the modern evolutionary synthesis, though scholars do not express it today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann became one of the first biologists to deny Lamarckism entirely. Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection. Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–1940, and "one of the great biologists of all time".
Essays Upon Heredity — a collection of Weismann's writing on hereditary issues.
Yawen Zou. 2015. The Germ-Plasm: a Theory of Heredity (1893), by August Weismann. The Embryo Project Encyclopedia.
Edwin G. Conklin. 1915. August Weismann. Proceedings of the American Philosophical Society, 54:3-12.
Hugo de Vries
(1848–1935)
Source: Wikipedia
Hugo Marie de Vries was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution. In 1889, De Vries published his book Intracellular Pangenesis, in which, based on a modified version of Charles Darwin's theory of Pangenesis of 1868, he postulated that different characters have different hereditary carriers. He specifically postulated that inheritance of specific traits in organisms comes in particles. He called these units pangenes, a term 20 years later to be shortened to genes by Wilhelm Johannsen.
Ralph E. Cleland. 1936. Hugo de Vries. Proceedings of the American Philosophical Society, 76:248-250.
Thomas Hunt Morgan
(1866–1945)
Source: Wikipedia
Thomas Hunt Morgan was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, Drosophila became a major model organism in contemporary genetics. The Division of Biology which he established at the California Institute of Technology has produced seven Nobel Prize winners.
Garland E. Allen. 1979. Thomas Hunt Morgan: The Man and His Science. Princeton: Princeton University Press. 447 pp. (The definitive biography)
Robert E. Kohler. 1994. Lords of the Fly: Drosophila Genetics and the Experimental Life. Chicago: University of Chicago Press. 344pp. (An excellent treatment of the early work in Drosophila genetics)
H. J. Muller. 1946. Thomas Hunt Morgan 1866–1945. Science, 103:550–551.
Diana E. Kenney and Gary G. Borisy. 2009. Thomas Hunt Morgan at the Marine Biological Laboratory: Naturalist and Experimentalist. Genetics, 181:841-846.
R. A. Fisher and G. R. de Beer. 1947. Thomas Hunt Morgan. 1866–1945. Obituary Notices of Fellows of the Royal Society, 5:451-466.
Stephen G. Brush. 2002. How Theories became Knowledge: Morgan's Chromosome Theory of Heredity in America and Britain. Journal of the History of Biology, 35:471–535.
Norman H. Horowitz. 1998. T. H. Morgan at Caltech: A Reminiscence. Genetics, 149:1629–1632.
Carl Woese
(1928–2012)
Source: Wikipedia
Carl Richard Woese was an American microbiologist and biophysicist. Woese is famous for defining the Archaea (a new domain or kingdom of life) in 1977 by phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese which revolutionized the discipline of microbiology. He was also the originator of the RNA world hypothesis in 1967, although not by that name. He held the Stanley O. Ikenberry Chair and was professor of microbiology at the University of Illinois at Urbana–Champaign. For much of the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry, morphology and metabolism. In a highly influential 1962 paper, Roger Stanier and C. B. van Niel first established the division of cellular organization into prokaryotes and eukaryotes, defining prokaryotes as those organisms lacking a cell nucleus. Stanier and Van Niel's concept was quickly accepted as the most important distinction among organisms; yet they were nevertheless skeptical of microbiologists' attempts to construct a natural phylogenetic classification of bacteria. However, it became generally assumed that all life shared a common prokaryotic (implied by the Greek root pro- (before, in front of) ancestor. In 1977, Carl Woese and George E. Fox experimentally disproved this universally held hypothesis about the basic structure of the tree of life. Woese and Fox discovered a kind of microbial life which they called the “archaebacteria” (Archaea). They reported that the archaebacteria comprised "a third kingdom" of life as distinct from bacteria as plants and animals. Having defined Archaea as a new "urkingdom" (later domain) which were neither bacteria nor eukaryotes, Woese redrew the taxonomic tree. His three-domain system, based on phylogenetic relationships rather than obvious morphological similarities, divided life into 23 main divisions, incorporated within three domains: Bacteria, Archaea, and Eucarya.
Looking in the Right Direction: Carl Woese and the New Biology
CONTENT: Tab H — HELP
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