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Carolus Linnaeus's Philosophia Botanica rejects any notion of evolution and continues his work in classifying plants.

Linnaeus's Species Plantarum completes his development of the use of binary nomenclature in botany. The work still provides the foundation for the modern classification of species.

Pierre-Louis de Maupertuis's Système de la Nature provides a theoretical speculation on heredity and the origin of species by chance.

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Joseph Gottlieb Kölreuter'S Vorläufige nachricht von einigen das geschlecht der pflantzen betreffende versuche and beobachtungen describes his research in heredity in plants.

Jean-Baptiste Robinet's five-volume De la nature claims that organic species form a linear scale of progress, without gaps.

Between 1761 and 1766, Joseph Gottlieb Kölreuter (Germany) demonstrates that hybrid offspring receive traits from both parents (pollen and ovule transmit genetic information), and are intermediate in most traits. First scientific hybrid produced (tobacco). Demonstrates the identity of reciprocal crosses. Notes hybrid vigor, segregation of offspring (parental and non-parental types) from a hybrid.

Charles Bonnet's Considerations sur les corps organisées gives his theory of "preformation" — the idea that each creature is already preformed in miniature in the egg, and that the egg contains all future generations in even smaller scale, ad infinitum.

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Charles Bonnet's Philosophical palingenesis, or ideas on the past and future states of living beings contains his view that the females of every species contain the germs of all future generations.

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The peculiar inheritance of human color-blindness reported to The Royal Society of London by Michael Lort.

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Johann Wolfgang Goethe's Versuch, die Metamorphose der Pflanzen zu erklären (Attempt to explain the metamorphosis of plants) claims incorrectly that all plant structures are modified leaves, but clearly espouses evolution.

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Erasmus Darwin (Charles' grandfather) publishes Zoonomia, or the Laws of Organic Life.

James Hutton publishes An Investigation of the Principles of Knowledge. Buried in the 2,138-page philosophical tome is a chapter about variety in nature in which Hutton anticipates Charles Darwin's theory of natural selection.

John Dalton's Extraordinary facts relating to the vision of colors gives an early account of red-green color blindness, which he refers to as Daltonism, since he is afflicted with the condition.

James Hutton's Theory of the Earth published, interpreting certain geological strata as former sea beds. Hutton proposes geological theory of gradualism.

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Publication of Thomas Malthus' Essay on the Principle of Population, a work that Darwin asserted helped him frame the principle of evolution by natural selection.

The first mammoth fossil fully documented by modern science is discovered near the delta of the Lena River in 1799 by Ossip Schumachov, a Siberian hunter. Schumachov allows it to thaw (a process taking several years) until he can retrieve the tusks for sale to the ivory trade in Yakutsk. He then abandons the specimen, allowing it to decay before its recovery. In 1806, Russian botanist Mikhail Adams rescues what remained of the specimen and brought it to the Zoological Museum of the Zoological Institute of the Russian Academy of Sciences in St. Petersburg. The specimen, which became known as the Adams Mammoth, is stuffed and mounted, and continues to be on display at the Zoological Institute.

Charles White publishes An Account of the Regular Gradation in Man, and in Different Animals and Vegetables, a treatise on the great chain of being, showing people of color at the bottom of the human chain.

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Jean-Baptiste Lamarck's Système de Animaux sans Vertèbres (System for Animals without Vertebrae) includes a classification system for invertebrates and a preliminary view of his ideas of evolution.

In Natural Theology, William Paley uses the analogy of a watch requiring a watchmaker to argue that the universe implies an intelligent designer.

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12 Feb 1809

Charles Darwin is born

Jean Baptiste de Lamarck's theory of evolution presented with the publication of his Philosophie Zoologique, which emphasized the fundamental unity of life and the capacity of species to vary.

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Swiss-French botanist Augustin Pyramus de Candolle introduces the word TAXONOMY in his lifelong project of a 21-volume plant encyclopedia. Seven volumes are published during his lifetime, the remainder after his death.

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Georges Cuvier's Le règne animal distribué d'après son organisation (The animal kingdom, distributed according to its organization) gives an account of the whole animal kingdom, dividing it into four distinct groups.

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A baby, who would later become Queen Victoria of England, is born carrying a new genetic mutation. Three generations later, that mutation may have changed the course of history.

Christian Friedrich Nasse formulated Nasse's law: hemophilia occurs only in males and is passed on by unaffected females.

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Etienne Geoffroy publishes Anatomical Philosophy discussing similarities between skeletal structures — such as bat wings, paws and hands — that support the evolutionary claims of Lamarck. He also argues that arthropods and vertebrates have similar but inverse body plans, an assertion that will ultimately be widely accepted.

Between 1822-1824, Thomas Andrew Knight, John Goss, and Alexander Seton all independently perform crosses with the pea and observe dominance in the immediate progeny, and segregation of various hereditary characters in the next generation. However, they do not study later generations or determine the numerical ratios in which the characters are transmitted.

Thomas Andrew Knight confirms reports of dominance, recessivity, and segregation in peas, but does not detect regularities.

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Karl Ernst von Baer first demonstrated the mammalian ovum; he regarded the sperm cells as "Entozoa," i.e., parasites, and named them spermatozoa.

A year after discovering the mammalian egg cell, Karl Ernst von Baer publishes Entwickelungsgeschichte der Thiere tracing the developmental history of animals.

Publication of Karl Ernst von Baer's The Embryology of Animals which strongly opposed preformationism.

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Charles Lyell's multi-volume Principles of Geology appear (between 1830 amd 1833), advancing the theory of uniformitarianism, i.e., the view that geological formations are explainable in terms of forces and conditions observable at present.

Charles Darwin joins the crew of the HMS Beagle as the ship's naturalist. The Beagle plans a two-year voyage to map the coast of South America. This turns out to be a five-year trip.

Patrick Matthew publishes On Naval Timber and Arboriculture with an appendix describing what Charles Darwin will later name natural selection. After becoming aware of Matthew's hypothesis, Darwin will acknowledge it in a reprint of On the Origin of Species.

Robert Brown published his observations reporting the discovery and widespread occurrence of nuclei in cells.

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The first volume of the five-volume Recherches sur les poissons fossiles (Researches on Fossil Fishes) by Jean-Louis-Rodolphe Agassiz is published.

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While serving as scientific officer on the HMS Beagle, Charles Darwin visits the Galapagos Islands. He observes that the many varieties of finches on the islands seem to have developed from a common ancestor found on the mainland of South America.

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Charles Darwin formulates the theory of natural selection to explain evolution. Fearful of the reaction his theory will cause, he delays publishing.

M. J. Schleiden and T. Schwann develop the cell theory. Schleiden notes nucleoli within nuclei.

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Charles Darwin's Zoology of the Voyage of the Beagle appears.

Martin Barry expressed the belief that the spermatozoon enters the egg.

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Charles Darwin's book The Structure and Distribution of Coral Reefs being the first part of the geology of the voyage of the Beagle, is published. During the year Darwin composes an abstract of his theory of species evolution.

Carl Wilhelm von Nägeli (1817-1891) publishes Zur Entwicklungsgeschichte des Pollens. His paper describes cell division in plants with remarkable accuracy, and discusses seed formation in flowering plants.

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Charles Darwin first outlines his thoughts on natural selection in an unpublished essay.

Robert Chambers, a Scottish journalist, publishes (anonymously) his Vestiges of the Natural History of Creation, an early book outlining an evolutionary view of the natural world.

The second part of the Geology of the Beagle, Charles Darwin's Geological Observations on Volcanic Islands Visited During the Voyage of H.M.S. Beagle, is published. Darwin's book claims to supply evidence for the geological theories of Charles Lyell (1797-1875), from areas that Lyell himself had never seen.

That all the cells in an organism are generated from successive divisions of the egg cell is described by Rudolf Albert von Kölliker (1817-1905). Kölliker shows that the egg is itself a cell.

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Jakob Mathias Schleiden and Theodor Schwann announce that cells are the basic units of all living structures.

On the archetype and homologies of the vertebrate skeleton, by Richard Owen (1804-1892), is published. In the book Owen argues that the skull, and other parts of the body, are formed by the modification of the vertebra of different animals.

Richard Owen describes "homologies" — similarities of design in bird wings, fish fins and human hands.

Botanist Carl Friedrich von Gärtner (1772-1850) publishes Versuche und Beobachtungen über die Bastarderzeugung im Pflanzenreiche. The book describes thousands of experiments, many involving the production of hybrids, on more than 500 species of plants. Mendel will study this book in detail when he attends the University of Vienna in the early 1850s, and will cite the book in the opening of his paper of 1865.

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Alfred Russel Wallace publishes "On the Law which has Regulated the Introduction of New Species," anticipating Darwin's theory of evolution by natural selection.

Rudolf Virchow states the principle that new cells come into being only by division of previously existing cells: Omnis cellula e cellula.

The remains of the first known example of what come to be known as the "Neanderthals" is found in a cave near Düsseldorf, in the Neander Valley. The discovery was made by limestone quarry miners and consists of a skullcap, two femora, the three right arm bones, two of the left arm bones, ilium, and fragments of a scapula and ribs. The fossils were given to Johann Carl Fuhlrott, a local teacher and amateur naturalist. The first description of the remains was made by anatomist Hermann Schaaffhausen and the find was announced jointly in 1857.In 1997, the specimen was the first to yield Neanderthal mitochondrial DNA fragments. The description of this discovery represents the beginning of paleoanthropology as a scientific discipline.

Louis Agassiz publishes Essay on Classification advocating a theory of multiple creations and contradicting both evolution and Noah's ark.

Gregor Mendel, a monk at the Augustinian monastery of St. Thomas in Brünn, Austria (now Brno, Czechoslovakia), begins breeding experiments with the garden pea, Pisum sativum.

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Rudolf Virchow finalizes the cell theory originally announced by Schleiden and Schwann 11 years earlier by declaring that cells are the basic units of all living things, and all cells are formed by the division of existing cells.

Alfred Russel Wallace sends to Darwin a manuscript — "On the Tendency of Varieties to Depart Indefinitely from the Original Type" — that shows clearly that Wallace has independently formulated a model of evolution by natural selection.

Darwin's and Wallace's ideas are jointly presented to the Linnaean Society of London.

Charles Darwin publishes On the Origin of Species.

Louis Agassiz attacks Darwin's the origin of species, rejecting the idea of evolution of the species and arguing that each species was created separately.

Thomas Henry Huxley (sometimes known as Darwin's bulldog) clashes with Bishop "Soapy Sam" Wilberforce about evolution at the annual meeting of The British Association for the Advancement of Science, in what has come to be known as the Huxley-Wilberforce debate.

Bishop Wilberforce is supposed to have asked Huxley sarcastically whether "it was through his grandfather or his grandmother that he claimed descent from a monkey." Huxley responded, "If then the question is put to me whether I would rather have a miserable ape for a grandfather or a man highly endowed by nature and possessed of great means of influence and yet employs these faculties and that influence for the mere purpose of introducing ridicule into a grave scientific discussion, I unhesitatingly affirm my preference for the ape." Or words to that effect.

Between 1861 and 1862, Max Johann Sigismund Schultze (Germany) and Heinrich Anton de Bary (Germany) establish the essential unity of protoplasm in all living cells.

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Alfred Russel Wallace describes the "Wallace line," the dividing line between Indo-Malayan and Austro-Malayan fauna, in Proceedings of the Royal Geographical Society of London.

Dominique Alexandre Godron and Charles Victor Naudin (France) independently report experiments in plant hybridization. Naudin confirmed Sageret's work, in general discussed work of the early hybridizers, and reported dominance and segregation in Datura (jimsonweed) hybrids. He did not deal with single characters and reported no statistical observations on the second generation. His theoretical explanation of his facts was a forerunner of Mendel's ideas, but inferred rather than deduced.

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Franz Schweigger-Seidel and A. von la Valette St. George (Germany) independently prove that a spermatozoon is a single cell and contains nucleus and cytoplasm

Gregor Mendel presents his work on inheritance in peas to the Brünn Natural History Society. The results are published the following year.

German zoologist Ernst Haeckel publishes General Morphology of Organisms, the first detailed genealogical tree relating all known organisms, incorporating the principles of Darwinian evolution.

Ernst Heinrich Haeckel (Häckel) hypothesizes that the nucleus of a cell transmits its hereditary information.

Mendel publishes his work on heredity, Versuche über Pflanzen Hybriden.

H. S. Bidwell (United States) reports controlled pollination in maize.

Charles Darwin publishes The Variation of Animals and Plants under Domestication, in which he offers his own theory of heredity, which he called the "Provisional Hypothesis of Pangenesis."

Ernst Haeckel publishes Natürliche Schöpfungsgeschichte, subdividing humanity into 12 separate species. He also asserts that evolution consists of 22 phases, the 21st being the "missing link" between apes and humans.

Thomas Henry Huxley publishes "On the Animals which are Most Nearly Intermediate between Birds and Reptiles," arguing that birds are descendants of dinosaurs. This suggestion will not be taken very seriously for another century.

Francis Galton publishes Hereditary Genius. In it he describes a scientific study of human pedigrees from which he concludes that intelligence has a genetic basis.

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Publication of Charles Darwin's Descent of Man, in which the role of sexual selection in evolution is described for the first time.

Lord Kelvin suggests that "the germs of life might have been brought to the Earth by some meteorite," an idea that will enjoy support a century later.

Johann Friedrich Miescher isolates a substance which he calls NUCLEIN from the nuclei of white blood cells. The substance was soluble in alkalis but not in acids and came to be known as nucleic acid.

Lambert Adolphe Jacques Quetelet showed the importance of statistical analysis for biologists and laid the foundation of biometry.

Ferdinand Julius Cohn coined the term BACTERIUM and founded the study of bacteriology.

Anton Schneider observed and described the behavior of nuclear filaments (chromosomes) during cell division in his study of the platyhelminth Mesostoma. His account was the first accurate description of the process of mitosis in animal cells.

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Eduard Strasburger accurately described the processes of mitotic cell division in plants.

Francis Galton demonstrates the usefulness of twin studies for elucidating the relative influence of nature (heredity) and nurture (environment) upon behavioral traits.

Oscar Hertwig concludes from a study on sea urchins that fertilization in both animals and plants consists of the physical union of the two nuclei contributed by the male and female parents.

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Hermann Fol reports watching the spermatozoan of a starfish penetrate the egg. He was able to see the transfer of the intact nucleus of the sperm into the egg, where it became the male pronucleus.

Wilhelm Friedrich Kühne proposed the term ENZYME (meaning "in yeast") and distinguished enzymes from the micro-organisms that produce them.

From 1879 through 1882, Walther Flemming describes and names CHROMATIN, MITOSIS, and the SPIREME. He makes the first accurate counts of chromosome numbers and accurately drew the "longitudinal splitting" of chromosomes.

Throughout the decade of 1880-1890, Walther Flemming, Eduard Strasburger, Edouard van Beneden, and others elucidate the essential facts of cell division and stressed the importance of the qualitative and quantitative equality of chromosome distribution to daughter cells.

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Walther Flemming publishes accurate depictions of cell division (mitosis) in Zellsubstanz, Kern und Zelltheilung.

Eduard Strasburger coins the terms CYTOPLASM and NUCLEOPLASM.

W. Flemming discovers lampbrush chromosomes and coins the term MITOSIS.

August Weismann points out the distinction in animals between the somatic cell line and the germ cells, stressing that only changes in germ cells are transmitted to further generations.

Edouard van Beneden announced the principles of genetic continuity of chromosomes and reported the occurrence of chromosome reduction at germ cell formation. The sperm and egg are haploid and fertilization restores the diploid chromosome number.

Wilhelm Roux offers a possible explanation for the function of mitosis.

William Keith Brooks, a professor at The Johns Hopkins University, publishes The Law of Heredity: A Study of the Cause of Variation and the Origin of Living Organisms. Although this speculative work did not significantly advance the understanding of heredity, brooks' thinking is important because during his career he provided instruction to and supervised the early research of Thomas H. Morgan, Edmund Beecher Wilson, and William Bateson — ultimately some of the most important contributors to the new science of genetics.

During 1884-88, identification of the cell nucleus as the basis for inheritance was independently reported by Oscar Hertwig, Eduard Strasburger, Albrecht von Kölliker, and August Weismann.

Gregor Mendel dies on January 6th, without ever knowing that his work on peas would lead to the transformation of biological research.

Walther Flemming, Eduard Strasburger and Edouard van Beneden demonstrate that chromosome doubling occurs by a process of longitudinal splitting. Strasburger describes and names the PROPHASE, METAPHASE, and ANAPHASEstages of chromosomal division.

August Weismann formulates the germ-plasm theory which held that the germ plasm was separate from the somatoplasm and was continuous from generation to generation.

Carl Rabl theorized the individuality of chromosomes in all stages of the cell cycle.

Walther Flemming observed sister chromatids passing to opposite poles of the cell during mitosis.

Francis Galton devised a new useful statistical tool, the correlation table.

Hugo de Vries (Holland) discovers aberrant evening primrose plants at Hilversum, Holland. Experiments with these extending over 15 years formed the basis for his mutation theory of evolution.

August Weismann elaborated an all-encompassing theory of chromosome behavior during cell division and fertilization and predicted the occurrence of a reduction division (meiosis) in all sexual organisms.

Edouard van Beneden demonstrated chromosome reduction in gamete maturation, thereby confirming August Weismann's predictions.

Wilhelm Roux put forth the suggestion that the linearly arranged qualities of the chromosomes were equally transmitted to both daughter cells at meiosis.

German anatomist W. von Waldeyer names chromosomes.

Heinrich Wilhelm Gottfried von Waldeyer names the CHROMOSOME.

Theodor Boveri verifies August Weismann's predictions of chromosome reduction by direct observation in Ascaris.

Francis Galton publishes Natural Inheritance. In it he describes the quantitative measurement of metric traits in populations. He thus founds biometry and the statistical study of variation. Ultimately, he formulates the Law of Ancestral Inheritance, a statistical description of the relative contributions to heredity made by one's ancestors.

The numerical equality of paternal and maternal chromosomes at fertilization was established by Theodor Boveri and Jean-Louis-Léon Guignard.

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Publication of August Weismann's book Das Keimplasma (The Germ Plasm) emphasized meiosis as an exact mechanism of chromosome distribution.

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Hans Driesch expounded the view that all nuclei of an organism were equipotential but varied in their activity in accordance with the differentiation of tissues.

Karl Pearson published the first in a long series of contributions to the mathematical theory of evolution. Methods for analyzing statistical frequency distributions were developed in detail.

William Bateson's Materials for the Study of Variation emphasized the importance of discontinuous variations, foreshadowing the rediscovery of Mendel's work.

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E. B. Wilson publishes The Cell in Development and Heredity. This influential treatise (ultimately reprinted in several editions) distills the information compiled concerning cytology in the half-century since Schleiden and Schwann put forth the cell theory.

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L. Cuénot (France) working with animals, and Strasburger (Germany) working with plants, advance theory that sex is controlled within the germ cell, not by environment.

Richard Altmann renames "nuclein" as NUCLEIC ACID.

The First International Congress of Genetics held in London.

William Bateson writes a paper on hybridisation and cross-breeding as a method of scientific investigation that anticipates Mendel's rediscovery.

H. de Vries, C. Correns, and E. Tschermak independently rediscover Mendel's paper. Using several plant species, de Vries and Correns had performed breeding experiments that paralleled Mendel's earlier studies and had independently arrived at similar interpretations of their results. Therefore, upon reading Mendel's publication they immediately recognized its significance. W. Bateson also stresses the importance of Mendel's contribution in an address to the Royal Society of London.

K. Landsteiner discovers the blood-agglutination phenomenon in man.

Karl Pearson develops the chi-square test.

H. de Vries adopts the term MUTATION to describe sudden, spontaneous, drastic alterations in the hereditary material of Oenothera.

T. H. Montgomery studies spermatogenesis in various species of Hemiptera. He concludes that maternal chromosomes only pair with paternal chromosomes during meiosis.

Archibald Garrod, a British physician, reports that alkaptonuria (a human disease) seems to be inherited as a Mendelian recessive.

C. E. McClung argues that particular chromosomes determine the sex of the individual carrying them, not just in insects, but perhaps in other species (including man).

Walter Sutton concludes that (a) chromosomes have individuality, (b) that they occur in pairs, with one member of each pair contributed by each parent, and (c) that the paired chromosomes separate from each other during meiosis.

T. Boveri studies sea urchin embryos and finds that in order to develop normally, the organism must have a full set of chromosomes, and from this he concludes that the individual chromosomes must carry different essential hereditary determinants.

William Bateson coins terms that will become essential to describing findings in the new science of heredity: GENETICS, F₁, F₂, ALLELOMORPH (later shortened to ALLELE), HOMOZYGOTE, HETEROZYGOTE, and EPISTASIS.

The concepts of PHENOTYPE, GENOTYPE, and SELECTION were introduced and clearly defined by Wilhelm Ludwig Johannsen.

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K. S. Merezhkovsky suggests that chloroplasts originated as a cyanobacterium swallowed by a protozoan, i.e., algal and plant cells result from two independent organisms that became symbionts. The idea will be largely forgotten until it is suggested again in the 1960s.

Lucien Claude Cuénot performs crosses between mice carrying a gene that gives them yellow fur. Since they always produce yellow furred and agouti offspring in a 2:1 ratio, he concludes they are heterozygous. (In 1910, W. E. Castle and C. C. Little will show that yellow homozygotes die in utero. This dominant allele is thus the first gene shown to behave as a homozygous lethal.)

William Bateson and Reginald Crundall Punnett report the discovery of two new genetic principles: LINKAGE and GENE INTERACTION.

(no entry for this year)

Godfrey Harold Hardy, a Cambridge mathematician, writes a letter to the editor of Science, suggesting that Mendelian mechanisms acting alone have no effect on allele frequencies. The letter begins, 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,... This short (less than one page) letter constitutes Hardy's entire lifetime contribution to the field of biology, yet still forms the mathematical basis for population genetics.

T. H. Morgan, later to become the first recipient of the Nobel Prize for work in genetics, writes a paper expressing doubts about the profusion of Mendelian explanations for inherited properties.

A. E. Garrod publishes Inborn Errors of Metabolism, the earliest discussion of the biochemical genetics of man (or any other species).

George H. Shull advocates the use of self-fertilized lines in production of commercial seed corn. The hybrid corn program that resulted, created an abundance of foodstuffs worth billions of dollars.

H. Nilsson Ehle puts forward the multiple-factor hypothesis to explain the quantitative inheritance of seed-coat color in wheat.

W. Johannsen's studies of the inheritance of seed size in self-fertilized lines of beans leads him to realize the necessity of distinguishing between the appearance of an organism and its genetic constitution. He invents the terms PHENOTYOPE and GENOTYPE to serve this purpose, and he also coins the word GENE.

T. H. Morgan discovers white eye and consequently sex linkage in Drosophila. Drosophila genetics begins.

T. H. Morgan proposes that the genes for white eyes, yellow body, and miniature wings in Drosophila are linked together on the X chromosome.

(no entry for this year)

A. H. Sturtevant, an undergraduate working with Morgan at Columbia, provides the experimental basis for the linkage concept in Drosophila and produces the first GENETIC MAP.

Calvin Blackman Bridges reports nondisjunction of sex chromosomes as PROOF of the chromosome theory of heredity.

Calvin Bridges identifies strains of mutant fruit flies with extra pairs of wings. Decades later, these strains will help biologists understand Hox genes that control the head-to-toe anatomy of widely varying animals.

Frederick Twort discovers a virus capable of infecting and destroying bacteria.

Thomas Hunt Morgan, Alfred Henry Sturtevant, Calvin Blackman Bridges, and Hermann Joseph Muller publish The Mechanism of Mendelian Heredity. This monograph provides the first systematic description of the actual mechanisms that control inheritance as evidenced in the Mendelian model. Here, for the first time, the gene is made real.

(no entry for this year)

British polymath D'Arcy Wentworth Thompson publishes On Growth and Form arguing that the forms Darwinian natural selection can produce through evolution are constrained by physical and mathematical laws, and that organic structures often emulate inorganic natural structures. His analysis led the way for the scientific explanation of morphogenesis, the process by which patterns and body structures are formed in plants and animals. Thompson's description of the mathematical beauty of nature and the mathematical basis of the forms of animals stimulated thinkers as diverse as Julian Huxley, Conrad Hal Waddington, Alan Turing, Claude LTvi-Strauss, Eduardo Paolozzi, Le Corbusier, and Mies van der Rohe.

C. B. Bridges discovers the first chromosome deficiency in Drosophila.

Felix Hubert D'Herelle, independently of Frederick Twort, discovers a virus capable of infecting and destroying bacteria, which he calls a BACTERIOPHAGE.

(no entry for this year)

Thomas Hunt Morgan and coworkers publish The Physical Basis of Heredity, a book-length summary of the rapidly growing findings in genetics.

C. B. Bridges discovers chromosomal duplications in Drosophila.

T. H. Morgan calls attention to the equality in Drosophila melanogaster between the number of linkage groups and the haploid number of chromosomes.

(no entry for this year)

(no entry for this year)

Lillian V. Morgan discovers attached-X chromosomes in Drosophila.

A. E. Boycott and C. Diver describe "delayed" Mendelian inheritance controlling the direction of the coiling of the shell in the snail Limnea peregra. A. H. Sturtevant suggests that the direction of coiling of the Limnea shell is determined by the character of the ooplasm, which is in turn controlled by the mother's genotype.

C. B. Bridges discovers chromosomal translocations in Drosophila.

(no entry for this year)

Tennessee schoolteacher John Thomas Scopes is tried for teaching evolution in the famous "Scopes Monkey Trial." Two-time presidential candidate William Jennings Bryan leads the prosecution. Labor lawyer Clarence Darrow leads the defense and goads Bryan into declaring that humans are not mammals. The conviction will be overturned on a technicality, and the anti- evolution law will remain on the books for decades.

A. H. Sturtevant analyzes the Bar-eye phenomenon in Drosophila and discovers position effect.

A. H. Sturtevant finds the first inversion in Drosophila.

Bernard O. Dodge initiates genetic studies on Neurospora.

H. J. Muller reports the artificial induction of mutations in Drosophila by x-rays.

J. B. S. Haldane suggests that the genes known to control certain coat colors in various rodents and carnivores may be evolutionarily homologous.

Frederick Griffith discovers type-transformation of pneumococci. This lays the foundation for the work of Avery, MacLeod, and McCarthy (1944).

L. J. Stadler reports the artificial induction of mutations in maize, and demonstrates that the dose-frequency curve is linear.

(no entry for this year)

R. A. Fisher publishes Genetical Theory of Natural Selection, a formal analysis of the mathematics of selection.

C. Stern, and independently H. B. Creighton and B. McClintock, provide the cytological proof of crossing over.

(no entry for this year)

Robert Broom publishes The Coming of Man: Was it Accident or Design? arguing that evolution is really driven by spiritual agencies, some with conflicting priorities, and that mankind is the ultimate aim of all evolution.

T. H. Morgan receives a Nobel Prize in Medicine for his development of the theory of the gene. He is the first geneticist to receive this award.

Barbara McClintock demonstrates in maize that a single exchange within the inversion loop of a paracentric inversion heterozygote generates an acentric and a dicentric chromatid.

T. S. Painter initiates cytogenetic studies on the salivary gland chromosomes of Drosophila.

(no entry for this year)

C. B. Bridges publishes the salivary gland chromosome maps for Drosophila melanogaster.

G. W. Beadle and B. Ephrussi and A. Kuhn and A. Butenandt work out the biochemical genetics of eye-pigment synthesis in Drosophila and Ephestia, respectively.

J. B. S. Haldane is the first to calculate the spontaneous mutation frequency of a human gene.

A. H. Sturtevant and T. Dobzhansky publish the first account of the use of inversions in constructing a chromosomal phylogenetic tree.

T. Dobzhansky publishes Genetics and the Origin of Species — a milestone in evolutionary genetics.

(no entry for this year)

E. L. Ellis and M. Delbrück perform studies on coliphage growth that mark the beginning of modem phage work. They devise the "one-step growth" experiment, which demonstrates that after the phage adsorbs onto the bacterium, it replicates within the bacterium during the "latent period," and finally the progeny are released in a "burst."

(no entry for this year)

G. W. Beadle and E. L. Tatum publish their classic study on the biochemical genetics of Neurospora and promulgate the ONE-GENE, ONE-ENZYME theory.

K. Mather coins the term polygenes and describes polygenic traits in various organisms.

Ernst Mayr publishes Systematics and the Origin of Species, and Julian Huxley publishes Evolution: The Modern Synthesis. Both books are significant contributions to the neo darwinian synthesis combining elements of natural selection, genetics, mutation, population biology and paleontology.

S. E. Luria and T. F. Anderson publish the first electron micrographs of bacterial viruses. T2 has a polyhedral body and a tail.

S. E. Luria and M. Delbrück initiate the field of bacterial genetics when they demonstrate unambiguously that bacteria undergo spontaneous mutation.

Theoretical physicist Erwin Schrödinger publishes What is Life? arguing that living organisms store and pass along information, perhaps using something like Morse code. This book will inspire James Watson, Francis Crick and Maurice Wilkins, who will share the Nobel prize for discovering the structure of DNA.

O. T. Avery, C. M. MacLeod, and M. McCarty describe the pneumococcus transforming principle. The fact that it is rich in DNA suggests that DNA and not protein is the hereditary chemical.

S. E. Luria demonstrates that mutations occur in bacterial viruses.

James B. Sumner, John H. Northrop, and Wendell M. Stanley share a Nobel Prize in Chemistry for Sumner's discovery that enzymes can be crystallized and for Northrop and Stanley's preparation of enzymes and virus proteins in a pure form.

Nobel Prize in Medicine awarded to H. J. Muller for his contributions to radiation genetics

Genetic recombination in bacteriophage is demonstrated by M. Delbrück and W. T. Bailey and by A. D. Hershey.

J. Lederberg and E. L. Tatum demonstrate genetic recombination in bacteria.

(no entry for this year)

H. J. Muller coins the term dosage compensation.

J. Lederberg and N. Zinder, and, independently, B. D. Davis develop the penicillin selection technique for isolating biochemically deficient bacterial mutants.

A. D. Hershey and R. Rotman demonstrate that genetic recombination occurs in bacteriophage.

J. V. Neel provides genetic evidence that the sickle-cell disease is inherited as a simple Mendelian autosomal recessive.

At a Cold Spring Harbor Symposium, Ernst Mayr argues that all hominid specimens so far found should be categorized in the genus Homo: H. transvaalensis, H. erectus, and H. sapiens.

E. Chargaff lays the foundations for nucleic acid structural studies by his analytical work. He demonstrates for DNA that the numbers of adenine and thymine groups are always equal and so are the numbers of guanine and cytosine groups. These findings later suggest to Watson and Crick that DNA consists of two polynucleotide strands joined by hydrogen bonding between A and T and between G and C.

E. M. Lederberg discovers lambda, the first viral episome of E. coli.

Barbara McClintock publishes a paper describing "jumping" genes that can move around within an organism's genome.

A. D. Hershey and M. Chase demonstrate that the DNA of phage enters the host, whereas most of the protein remains behind.

F. Sanger and his colleagues work out the complete amino acid sequence for the protein hormone insulin, and show that it contains two polypeptide chains held together by disulfide bridges.

J. Lederberg and E. M. Lederberg invent the replica plating technique.

N. D. Zinder and J. Lederberg describe transduction in Salmonella.

J. D. Watson and F. H. C. Crick propose a model for DNA comprised of two helically intertwined chains tied together by hydrogen bonds between the purines and pyrimidines.

W. Hayes discovers polarized behavior in bacterial recombinations. He isolates the Hfr H strain of E. coli and shows that certain genes are readily transferred from Hfr to F- bacteria, whereas others are not.

(no entry for this year)

S. Benzer works out the fine structure of the rII region of phage T4 of E. coli, and coins the terms CISTRON,RECON, and MUTON.

F. Jacob and E. L. Wollman are able experimentally to interrupt the mating process in E. coli and show that a piece of DNA is inserted from the donor bacterium into the recipient.

Francis Crick proposes the "central dogma" of genetic information transfer: DNA specifies RNA and RNA specifies cell proteins.

V. M. Ingram reports that normal and sickle-cell hemoglobin differ by a single amino acid substitution.

Frederick Sanger receives a Nobel Prize in Chemistry for his work on the structure of proteins, especially that of insulin.

George W. Beadle, Edward L. Tatum, and Joshua Lederberg share a Nobel Prize in Medicine for Beadle and Tatum's discovery that genes act by regulating definite chemical events, and for Lederberg's discoveries concerning genetic recombination and the organization of the genetic material of bacteria.

F. H. C. Crick suggests that during protein formation the amino acid is carried to the template by an adaptor molecule containing nucleotides and that the adaptor is the part that actually fits on the RNA template. Crick thus predicts the discovery of transfer RNA.

F. Jacob and E. L. Wollman demonstrate that the single linkage group of E. coli is circular and suggest that the different linkage groups found in different Hfr strains result from the insertion at different points of a factor in the circular linkage group that determines the rupture of the circle.

M. Meselson and F. W. Stahl use the density gradient equilibrium centrifugation technique to demonstrate the semiconservative distribution of density label during DNA replication in E. coli.

Severo Ochoa and Arthur Kornberg share a Nobel Prize in Medicine for their discovery of the mechanisms in the biological synthesis of ribonucleic acid and deoxiribonucleic acid.

J. Lejeune, M. Gautier, and R. Turpin show that Down syndrome is a chromosomal aberration involving trisomy of a small telocentric chromosome.

R. L. Sinsheimer demonstrates that bacteriophage phiX174 of E. coli contains a single-stranded DNA molecule.

Alister Hardy promotes his Homo aquaticus or "aquatic ape" hypothesis to the British Sub Aqua Club. He will follow up this announcement with several magazine articles.

F. Jacob and J. Monod publish "Genetic regulatory mechanisms in the synthesis of proteins," a paper in which the theory of the OPERON is developed.

Human geneticist James Neel develops the "thrifty genotype" hypothesis that human ancestors endured feast-famine cycles that made the human body very effective in storing fat for lean times.

James Watson, Francis Crick, and Maurice Wilkins share a Nobel Prize in Medicine for their work in elucidating the structure of DNA.

(no entry for this year)

(no entry for this year)

François Jacob, André Lwoff, and Jacques Monod share a Nobel Prize in Medicine for their discoveries concerning genetic control of enzyme and virus synthesis.

Willi Hennig works on a new approach to assessing evolutionary relationships, known as cladistics. Although it will be hotly debated, this technique will eventually become standard practice in paleontology, botany and zoology.

Lynn Sagan (later Lynn Margulis) hypothesizes that chloroplasts originated as cyanobacteria, and that mitochondria originated as bacteria. She suggests that both were engulfed by other cells and began functioning as symbionts.

A.G. Cairns-Smith publishes a paper suggesting that the first life on Earth might have been fine-grained clay crystals. He will publish on this topic several more times before his death, but the experimental evidence will remain scant, perhaps in part because sufficient technology doesn't yet exist to test the hypothesis.

Robert W. Holley, Har Gobind Khorana, and Marshall W. Nirenberg share a Nobel Prize in Medicine for their interpretation of the genetic code and its function in protein synthesis.

R. H. Whittaker proposes to divide all living things into five kingdoms: Animalia, Plantae, Fungi, Protista and Monera.

Max Delbrück, Alfred D. Hershey, and Salvador E. Luria share a Nobel Prize in Medicine for their discoveries concerning the replication mechanism and the genetic structure of viruses.

(no entry for this year)

Five pairs of adult wall lizards are moved between two islands in Croatia. Over the next few decades, the lizards on the new island will evolve larger heads, stronger bites, and a greater tolerance for an herbivorous diet than the original lizard population.

Stephen Jay Gould and Niles Eldredge publish their theory of punctuated equilibrium, stating that evolution often occurs in short bursts, followed by long periods of stability.

Christian B. Anfinsen, Stanford Moore, and William H. Stein share a Nobel Prize in Chemistry, with Anfinsen cited for his work on ribonuclease, especially concerning the connection between the amino acid sequence and the biologically active conformation, and Moore and Stein cited for their contribution to the understanding of the connection between chemical structure and catalytic activity of the active centre of the ribonuclease molecule.

Half in jest, Francis Crick and Leslie Orgel suggest that ancient aliens may have seeded the early Earth with DNA, and all life on this planet arose from that.

Peter and Rosemary Grant begin a long-term study of finches on the Galápagos Islands. In succeeding years, as they watch finches adapt to alternating wet and dry conditions, the Grants will uncover evidence that evolution proceeds more rapidly than what Darwin estimated.

Taking a line from Through the Looking Glass, Leigh Van Valen establishes the "Red Queen" hypothesis of coevolution between predator and prey: "it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!"

(no entry for this year)

Mary-Claire King and Allan Wilson publish their finding that human and chimpanzee DNA sequences differ by roughly 1 percent, meaning humans have more in common with chimps than chimps do with gorillas. King and Wilson suggest that humans and chimps differ largely in the DNA that switches on and off genes.

David Baltimore, Renato Dulbecco, and Howard Temin share Nobel Prize in Medicine for their discoveries concerning the interaction between tumour viruses and the genetic material of the cell.

Overturning the classifications introduced by R. H. Whittaker seven years earlier, Carl Woese proposes to divide all living things into three categories: Bacteria, Archaea and Eukarya.

Submersible vehicle Alvin reveals deep sea vents on the ocean floor that give rise to an ecosystem owing nothing to photosynthesis. This finding prompts speculation that life on Earth first arose in deep-sea, not shallow-water, ecosystems.

Fred Sanger and collaborators publish the first complete DNA sequence of an organism, a bacteriophage, or virus infecting bacteria.

Werner Arber, Dan Nathans, and Hamilton Smith share a Nobel Prize in Medicine for the discovery of restriction enzymes and their application to problems of molecular genetics.

Fresh out of law school and short on cash, Robert Heggestad buys an antique cabinet on an installment plan from a Virginia antique shop. The cabinet turns out to contain some 1,700 plant and invertebrate specimens from the personal collection of Alfred Russel Wallace.

Christiane Nüsslein-Volhard and Eric Wieschaus describe genetic mutations affecting the body plan of the fruit fly Drosophila, and identify genes controlling the basic body plans of all animals. These genes will eventually be known as Hox genes.

Paul Berg, Walter Gilbert, and Frederick Sanger share a Nobel Prize in Chemistry, with Berg cited for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant-DNA, and Gilbert and Sanger cited for their contributions concerning the determination of base sequences in nucleic acids. This is Sanger's second Nobel, the first having come in 1958 for his work on the structure of insulin.

(no entry for this year)

(no entry for this year)

Barbara McClintock receives the Nobel Prize in Medicine for her discovery of mobile genetic elements.

David Raup and Jack Sepkoski publish the controversial claim that mass extinctions are regularly spaced at 26 million years.

(no entry for this year)

(no entry for this year)

Allan Wilson and Rebecca Cann announce that all humans share a common ancestor who lived in Africa as recently as 150,000 years ago. Because the discovery is based on examination of mitochondrial DNA, the ancestral entity will be given the popular (and somewhat misleading) name of "Mitochondrial Eve." The controversial finding will be supported by another discovery in 2000.

Molecular biologist John Cairns describes experiments suggesting that bacteria facing environmental stress can "direct" their mutations to produce favorable adaptations. Directed mutation will remain a controversial idea, but the possibility that organisms mutate at a greater rate (hypermutation) under environmental stress will gain more acceptance.

Sidney Altman and Thomas R. Cech share a Nobel Prize in Chemistry for their discovery of catalytic properties of RNA.

The Human Genome Project is launched with the goal of sequencing all 3 billion base pairs of human DNA by 2005.

Chicxulub crater is discovered in the Yucatán Peninsula, supporting the asteroid impact theory first suggested in 1980.

(no entry for this year)

Kary Mullis and Michael Smith share a Nobel Prize in Chemistry, with Mullis cited for his contributions to the developments of methods within DNA-based chemistry and Smith for his fundamental contributions to the establishment of oligonucleiotide-based, site-directed mutagenesis and its development for protein studies.

Richard J. Roberts, and Phillip A. Sharp share a Nobel Prize in Medicine for their discoveries of split genes.

(no entry for this year)

Edward B. Lewis, Christiane Nüsslein-Volhard, and Eric F. Wieschaus share a Nobel Prize in Medicine for their discoveries concerning the genetic control of early embryonic development.

Using "molecular clock" estimates of mutation rates, Greg Wray and collaborators hypothesize that metazoan phyla diverged from each other 1 billion years ago, or even earlier. In other words, they argue that metazoans existed hundreds of millions of years before the earliest metazoan fossils (about 600 million years old) yet found.

(no entry for this year)

(no entry for this year)

(no entry for this year)

Based on studies of Y chromosomes, Peter Underhill publishes his finding that all modern humans share a common ancestor, bolstering the 1987 announcement from Cann and Wilson. This suggests a "bottleneck" event (population crash) among human ancestors living in Africa roughly 150,000 years ago.

Sally McBearty and Alison Brooks publish "The Revolution that Wasn't" challenging the long-held notion of a "big bang" in human intellectual evolution approximately 40,000 years ago. Instead, they cite evidence for earlier appearances of modern behavior.

Alfred Sturtevant's A History of Genetics is republished jointly by the Electronic Scholarly Publishing Project and the Cold Spring Harbor Laboratory Press. Sturtevant provides an insider's perspective (he created the FIRST GENETIC MAP ) to this first-rate summary of the foundations of classical genetics.

CLICK HERE TO BUY THIS BOOK

The International Human Genome Sequencing Consortium (Human Genome Project) publishes the initial sequence and analysis of the human genome in Nature Magazine. Celera Genomics simultaneously publishes a draft human genome sequence in Science Magazine.

Leland H. Hartwell, R. Timothy Hunt, and Sir Paul M. Nurse share a Nobel Prize in Medicine for their discoveries of key regulators of the cell cycle.

Sydney Brenner, H. Robert Horvitz, and John E. Sulston share a Nobel Prize in Medicine for their discoveries concerning genetic regulation of organ development and programmed cell death.

(no entry for this year)

Peter Brown, Mike Morwood and collaborators announce the find of a 1-meter- tall hominid skeleton on the Indonesian island of Flores. Found near the remains of giant lizards and pygmy elephants, the new species is formally named Homo floresiensis and nicknamed the "hobbit." Though some suspect it's a kind of malformed, small-brained midget, this interpretation will be answered by braincase scans, wrist bones too primitive to be Homo sapiens, and the announcement of several more individuals of the same species. Later studies will suggest direct ancestry from Homo erectus, although another study will argue the remains really indicate Down syndrome. The species is initially given an estimated age as young as 11,000 years, but later research will indicate an age of at least 50,000 years.

(no entry for this year)

Jean Moliner, Gerhard Ries, Cyril Zipfel and Barbara Hohn publish their findings on stressed plants that not only mutate at a greater rate, but also pass an increased mutation tendency to their offspring.

Andrew Z. Fine and Craig C. Mello share a Nobel Prize in Medicine for their discovery of RNA interference — gene silencing by double-stranded RNA.

Roger D. Kornberg was awarded a Nobel Prize in Chemistry for his studies of the molecular basis of eukaryotic transcription.

Mario R. Capecchi, Sir Martin J. Evans, and Oliver Smithies share a Nobel Prize in Medicine for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells.

After studying grunting fish, Andrew Bass and colleagues report that the part of the brain controlling volcalization is extremely primitive, and propose that vertebrates evolved the ability to communicate through sound some 400 million years ago.

Gabriele Gentile and colleagues describe a previously overlooked pink iguana, referred to as "rosada," on the Galápagos Islands. The pink lizard species may represent the earliest divergence of land animals on the island chain that Charles Darwin made famous.

Elizabeth H. Blackburn, Carol W. Greider, and Jack W. Szostak share a Nobel Prize in Medicine for their discovery of how chromosomes are protected by telomeres and the enzyme telomerase.

Venkatraman Ramakrishnan, Thomas A. Steitz, and Ada E. Yonath share a Nobel Prize in Chemistry for their studies of the structure and function of the ribosome.

Ryan Kerney announces the discovery of algae (Oophila amblystomatis) living inside spotted salamander (Ambystoma maculatum) embryo cells — the first discovery of a photosynthetic symbiont living inside vertebrate cells.

Candy makers Hershey and Mars finance competing genomic sequences for cacao (the primary ingredient of chocolate).

Robert G. Edwards receives the Nobel prize in Medicine "for the development of in vitro fertilization"

Two studies released in the same week indicate that modern Melanesians and Aboriginal Australians descended from an earlier migration out of Africa than did other populations. Further, the studies suggest that participants in the earlier migration interbred with Denisovans.

Bruce A. Beutler and Jules A. Hoffmann share the Nobel Prize in Medicine "for their discoveries concerning the activation of innate immunity"

Sir John B. Gurdon and Shinya Yamanaka share the Novbel Prize in Medicine "for the discovery that mature cells can be reprogrammed to become pluripotent"

Based on new genetic research, David Reich, Svante Pääbo and collaborators announce at a Royal Society of London meeting that Denisovans bred with Neanderthals, ancestors of people now living in East Asia and Oceania, and another group of extinct archaic humans who were genetically dissimilar to both Neanderthals and modern humans. A few weeks later, Matthias Meyer, Svante Pääbo and coauthors describe the oldest hominin DNA sequence to date, from a 400,000-year-old femur from Spain's Sima de los Huesos. The mitochondrial DNA indicate an unexpected link to Denisovans.

Using genetic material from more than 300 individuals, including aboriginal Australians from the Northern Territory, a team of geneticists argues that Australians — long believed isolated from other populations for some 45,000 years — received substantial gene flow from India about 4,230 years ago.

James E. Rothman, Randy W. Schekman and Thomas C. Südhof share the Nobel Prize in Medicine "for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells"

John O’Keefe, May-Britt Moser and Edvard I. Moser share the Nobel Prize in Medicine "for their discoveries of cells that constitute a positioning system in the brain"

Bhart-Anjan Bhullar, Arhat Abzhanov and colleagues announce that they have reverse engineered dinosaur snouts in chicken embryos by altering beak- building gene expressions.

Stephen Hackley publishes a review article arguing that human brains retain vestigial neural circuitry, the same circuitry that currently allows other mammals (and once allowed our ancient ancestors) to orient their ears toward novel stimuli.

William C. Campbell and Satoshi Omura share the Nobel prize in Medicine "for their discoveries concerning a novel therapy against infections caused by roundworm parasites" and Tu Youyou receives a Nobel {rize in Medicine "for her discoveries concerning a novel therapy against Malaria"

Yoshinori Ohsumi receives the Nobel prize in Medicine "for his discoveries of mechanisms for autophagy"

Jeffrey C. Hall, Michael Rosbash and Michael W. Young share the Nobel Prize in Medicine "for their discoveries of molecular mechanisms controlling the circadian rhythm"

James P. Allison and Tasuku Honjo share the Nobel Prize in Medicine "for their discovery of cancer therapy by inhibition of negative immune regulation"

(no entry for this year)