ESP: Electronic Scholarly Publishing

. Bridges, Calvin B., and Olbrycht, T. M. 1926. Genetics, 11:41-55.

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A Diagram of Heredity. Galton, Francis. 1898. Nature, 57:293.

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Some standard textbook descriptions of early genetics give the impression that, besides Mendel, no one attempted any genetic analysis in the entire nineteenth century. This is far from the truth, with Francis Galton offering a fine refutation. Starting just a few years after Mendel (and also working with peas), Galton carried out a series of well-received studies that resulted in his "Ancestral Law of Heredity," summarized diagrammatically in this brief communication. Galton's "Law" was so firmly established in some circles, that many adherents did not accept Mendelism until 1918, when R. A. Fisher showed that Galton's Law was in fact a natural consequence of Mendelian inheritance for polygenic traits.

A History of Genetics. Sturtevant, Alfred H. 1965. First published in 1965, it was brought back into print in 2001 by Cold Spring Harbor Laboratory Press and the Electronic Scholarly Publishing project.

This is a full-text PDF typeset version of the entire 167-page original book.
Between 1910 and 1915, the modern chromosomal theory of heredity was established, largely through work done in the laboratory of Thomas H. Morgan at Columbia University. This book, by one of Morgan's students, presents the history of early genetics and captures the excitement as a new discipline was being born.

Sturtevant himself made major contributions to genetics, including the development of the world's first genetic map in 1913.

A Lecture on Mendelism. Drinkwater, H. 1910. London: J. M. Dent & Sons.

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This short book was based on a lecture given by Drinkwater as one of a series known as "Science Lectures for the People." The book provides insights into the general perception (as opposed to scholarly view) of genetics very early after the field had begun.

The book also contains some nice portraits of Mendel, Bateson, and Punnett.

A chronology of genetics. Cook, Robert. 1937. Yearbook of Agriculture, pp. 1457-1477.

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Robert Cook, as editor of The Journal of Heredity, was especially well positioned to appreciate how the new science of genetics developed after the rediscovery of Mendel in 1900 and the establishment of the chromosome theory of inheritance by T. H. Morgan and his students.

In this essay, Cook traces the history of genetics to four main roots - mathematics, plant breeding, animal breeding, and cytology.

A correlation of cytological and genetical crossing-over in Zea mays. Creighton, Harriet B., and McClintock, Barbara. 1931. PNAS, 17:492-497.

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When Alfred Sturtevant created the first genetic map, he hypothesized that genetic recombination resulted from the actual exchange of chromatid fragments. However, at the time there was no hard evidence that proved recombination is accomplished via such a mechanism. The same genetic results could be explained if only alleles are exchanged during recombination, leaving the bulk of the chromatid arm unaffected. Since the two hypotheses make equivalent predictions regarding the distribution of alleles, they cannot be distinguished using purely genetic methods.

Attempting to demonstrate that genetic recombination is accomplished via the physical exchange of chromatid arms poses a problem similar to that encountered by Thomas H. Morgan when he first hypothesized that genes might be carried on the X chromosome. Although Morgan’s genetic hypothesis of X-linkage provided an explanation for the inheritance of the white-eye allele in Drosophila, the notion that genes are actually carried on the X chromosome was not proven until Calvin Bridges provided cytological evidence to confirm the genetic observations. Bridges established a one-to-one correspondence between the abnormal distribution of eye-color alleles and the abnormal distribution of X chromosomes. That is, he established a relationship between genetic markers (the eye color alleles and their associated inheritance patterns) and cytological markers (the presence of abnormal sets of sex chromosomes).

In this paper, Creighton and McClintock present work in which they use a combination of cytological and genetic markers to show that cytological crossing-over occurs and that it is accompanied by genetical crossing-over.

At times, the authors’ discussion of their results can be difficult to follow. When this work was done, the authors could reasonably expect that any reader would be familiar with the underlying main question (is genetic and cytological recombination mediated by the same physical event?) and that readers would also be familiar with “chromosome mechanics” — that is, with interpreting experimental designs involving abnormal chromosomes. Because Creighton and McClintock could make such reasonable assumptions, they do not take much time to help readers understand the underlying logic or to appreciate the subtleties of the analysis. But, in just a few pages they do accomplish their goal of establishing the reality of cytological recombination and of showing that it is associated with genetic recombination. This paper is truly a classic paper.

A cytological basis for the Mendelian laws. Cannon, W. A. 1902. Bulletin of the Torrey Botanical Club, 29:657-661.

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A further analysis of loci in the so-called "inert region" of the X chromosome of Drosophila. Muller, Hermann J., Raffel, D., Gershenson, S. M., and Prokofya-Belgovskaya, A. A. 1937. Genetics, 22:87-93.

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A further study of the so-called mutation at the bar locus of Drosophila. Sturtevant, Alfred H. 1928. Genetics, 13:401-409.

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A new Method for the Study of Chromosome Maps in Drosophila melanogaster. Painter, Theophilus S. 1934. Genetics, 19: 175-188.

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Now, almost any reference to the genetics of Drosophila includes some illustration of the giant salivary gland chromosomes found in these flies. Although Drosophila had been used effectively since 1910, it was this paper by Painter that first showed the tremendous potential of these chromosomes for cytogenetic research. New discovery often hinges on new methods and this paper is truly a break-through study in genetic methodology.

A permanent memorial to Galton and Mendel. Shull, George H. 1923. The Scientific Monthly, 16: 263-270.

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In December of 1922, the American Society of Naturalists held a special session to honor the centenaries of the birth of Gregor Mendel and of Francis Galton. This is one of the four papers presented at that session and later published in the The Scientific Monthly.

A possible Mendelian explanation for a type of inheritance apparently non-Mendelian in nature Little, C. C. 1914. Science, 40:904-906.

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An Essay on the Principle of Population. Malthus, T. 1798.

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In 1798, Thomas Malthus anonymously published this Essay, outlining why the forces of population growth tend to create a "struggle for existence" (see page 14). This book had a significant influence on Darwin as he looked for mechanisms that might explain evolutionary change. The influence shows, with Chapter Three of Darwin's Origin of Species entitled "Struggle for Existence". Now, 200 years after its first publication, Malthus' work is still an interesting read.

Any Hereditary Character and the Kinds of Things We Need to Know About It. Riddle, Oscar. 1924. The American Naturalist, LVIII:410-425.

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This does not qualify as a classic genetics paper and I suspect that it has never before been included in a collection of important papers. However, it is included here because it provides a glimpse into some general aspects of genetic thought in the mid 1920's.

The premise of this essay is essentially that, as of its writing, " studies on heredity and evolution offer what is mainly a two-sided attack on a many-sided problem." This argument was well taken, but the modern reader may have difficulty appreciating other concerns of the essay.

Application for Support of an Experimental Investigation of Mendel's Principles of Heredity in Animals and Plants. Bateson, William. 1902. In Bateson, B. 1928. William Bateson, F.R.S.: His Essays & Addresses, together with a Short Account of his Life. Cambridge: Cambridge University Press.

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Although not considered to be one of the "official" rediscovers of Mendel's work, William Bateson was the first English-speaking scientist to recognize the importance of Mendel's work and he immediately set out to bring Mendel's work to the attention of the scientific community. Bateson coined the word "genetics" to name the new field and made many important contributions to its development.

This present document is a copy of a letter that Bateson wrote in 1902, seeking financial support from the Trustees of the Carnegie Institution for continued investigations into Mendelian mechanisms of inheritance.

The letter was almost certainly the world's first grant application in the new field of genetics. It was declined.

Artificial transmutation of the gene. Muller, Hermann J. 1927. Science, 46:84-87.

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Chromosomes and Heredity. Morgan, Thomas H. 1910. The American Naturalist, 44:449-496.

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Work in the laboratory of T. H. Morgan was critical in establishing that genes are real, physical entities and that they are arranged in a linear order on chromosomes. In this early, analytical paper, Morgan considers whether or not chromosomes might be carriers of the hereditary material and whether or not they might control sex determination.

Morgan's careful and logical approach is captured in his final comments on sex deteremination:

Science advances by carefully weighing all of the evidence at her command. When a decision is not warranted by the facts, experience teaches that it is wise to suspend judgment, until the evidence can be put to further test. This is the position we are in today concerning the interpretation of the mechanism that we have found by means of which sex is determined. I could, by ignoring the difficulties and by emphasizing the important discoveries that have been made, have implied that the problem of sex determination has been solved. I have tried rather to weigh the evidence, as it stands, in the spirit of the judge rather than in that of the advocate. One point at least I hope to have made evident, that we have discovered in the microscopic study of the germ cells a mechanism that is connected in some way with sex determination; and I have tried to show, also, that this mechanism accords precisely with that the experimental results seem to call for. The old view that sex is determined by external conditions is entirely disproven, and we have discovered an internal mechanism by means of which the equality of the sexes where equality exists is attained. We see how the results are automatically reached even if we can not entirely understand the details of the process. These discoveries mark a distinct advance in our study of this difficult problem.

Chromosomes and associative inheritance. Morgan, Thomas H. 1911. Science, New Series, 34:636-638.

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Chromosomes and heredity. Morgan, Thomas H. 1910. The American Naturalist, 44: 449-496.

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Between 1910 and 1915, work in Morgan's lab laid the foundation of the modern chromosomal theory of heredity. This paper represents Morgan's thinking early in this process.

The opening lines of his paper captures the the issues that he then deemed important to a consideration of the mechanism of heredity:

We have come to look upon the problem of heredity as identical with the problem of development. The word heredity stands for those properties of the germ-cells that find their expression in the developing and developed organism. When we speak of the transmission of characters from parent to offspring, we are speaking metaphorically; for we now realize that it is not characters that are transmitted to the child from the body of the parent, but that the parent carries over the material common to both parent and offspring. This point of view is so generally accepted to-day that I hesitate to restate it. It will serve at least to show that in what I am about to say regarding heredity and the germ-cells I shall ignore entirely the possibility that characters first acquired by the body are transmitted to the germ. Were there sufficient evidence to establish this view, our problem would be affected in so far as that we should not only have to account for the way in which the fertilized egg produces the characters of the adult, but also for the way in which the characters of the adult modify the germ-cells. The modern literature of development and heredity is permeated through and through by two contending or contrasting views as to how the germ produces the characters of the individual. One school looks upon the egg and sperm as containing samples or particles of all the characters of the species, race, line, or even of the individual. This view I shall speak of as the particulate theory of development. The other school interprets the egg or sperm as a kind of material capable of progressing in definite ways as it passes through a series of stages that we call its development. I shall call this view the theory of physico-chemical reaction, or briefly the reaction theory.

Complementary Factors for Eye Color in Drosophila. Wright, Sewall. 1932. The American Naturalist, LXVI:282-283.

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There are two distinct biochemical pathways producing pigments that color the eyes of Drosophila melanogaster -- one yields a bright red pigment, the other brown. When both are present, the eyes are dark-red. When one is present and the other absent, flies have brown or bright red eyes. When both are missing, flies have white eyes.

In 1932, Sewall Wright reported the first case where a cross between red-eyed and brown-eyed flies yielded double-recessive progeny with white eyes. What makes this observation interesting is that the work occurred as part of a class exercise in an undergraduate teaching laboratory at the University of Chicago. Not many modern undergraduate lab exercises yield publishable results.

Complete linkage in the second chromosome of the male of Drosophila Morgan, Thomas H. 1912. Science, 36:933-934.

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Concerning artificial crossing in Pisum sativum Tschermak, Erik von 1900. First published in English as: Tschermak, E. 1950. Concerning artificial crossing in Pisum sativum. Genetics, 35(5, pt 2): 42-47. Originally published as: Tschermak, E. 1900. Über Künstliche Kreuzung bei Pisum sativum. Berichte der Deutsche Botanischen Gesellschaft 18: 232-239, 1900.

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Tschermak, along with Carl Corren and Hugo de Vries, is considered to be one of the three co-discovers of Mendel's work in 1900. He had been working himself with garden peas when he rediscovered Mendel's prior contributions. In a postscript to his paper, he wrote:

Correns has just published experiments which also deal with artificial hybridization of different varieties of Pisum sativum and observations of the hybrids left to self-fertilization through several generations. They confirm, just as my own, Mendel's teachings. The simultaneous "discovery" of Mendel by Correns, de Vries, and myself appears to me especially gratifying. Even in the second year of experimentation, I too still believed that I had found something new.

Concerning the law of segregation of hybrids. Vries, Hugo de 1900. First published in English as: De Vries, H.. 1950. Concerning the law of segregation of hybrids. Genetics, 35(5, pt 2): 30-32. Originally published as: De Vries, H. 1900. Sur la loi de disjonction des hybrides. Comptes Rendus de l'Academie des Sciences (Paris), 130: 845-847.

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Hugo de Vries, along with Carl Correns and Erik von Tschermak, is considered to be one of the three co-discovers of Mendel's work in 1900. De Vries was by far the most established scientist at the time, with an established research record dealing with "mutations" (variations) and speciation.

In this first of two papers that he published in 1900, de Vries does not even mention Mendel by name, even though he adopts Mendelian terminology such as dominant and recessive.

Croonian Lecture: On the Mechanism of Heredity. Morgan, Thomas H. 1922. Proceedings of the Royal Society, B, 94:162-197.

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The Croonian Lecture is the Royal Society's premier lecture in the biological sciences. Dr Croone, one of the original members of the Society, left on his death in 1684 a scheme for two lectureships, one at the Royal Society and the other at the Royal College of Physicians

Morgan was invited to give the Croonian lecture in 1922 - a recognition of his pioneering work in elucidating the physical basis of heredity.

Crossing Over ohne Chiasmatypie? Goldschmidt, Richard 1917. Genetics, 2:82-95.

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Crossing Over without Chiasmatype? Sturtevant, A. H. 1917. Genetics, 2:301-304.

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Crossing over in the X chromosomes of triploid females of Drosophila melanogaster.. Bridges, Calvin B., and Anderson, E. G. 1925. Genetics, 10:418-441.

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Deficiency. Bridges, Calvin B. 1917. Genetics, 2:445-465.

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Direct proof through non-disjunction that the sex-linked genes of Drosophila are borne on the X-chromosome. Bridges, Calvin B. 1914. Science, NS vol. XL:107-109.

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Although Bridges' longer 1916 Genetics paper (vol 1, page 1) on the same topic is better known and treats the issue at much greater length, this short communication in Science contains the same argument and is equally persuasive.

By 1910, much evidence had been presented to demonstrate that sexual phenotype (i.e., maleness or femaleness) was determined by chromosomes. And, as early as 1902 Sutton noted that similarities in the behavior of genes and chromosomes suggested that Mendelian factors might be carried on chromosomes.

Here, Bridges shows that mis-assortment of the sex chromosomes is accompanied by atypical inheritance patterns for sex-linked traits and he argues that this proves that genes are carried on chromosomes. He concludes his paper: "there can be no doubt that the complete parallelism between the unique behavior of the chromosomes and the behavior of sex-linked genes and sex in this case means that the sex-linked genes are located in and borne by the X-chromosomes."

Essays Upon Heredity. Weismann, August 1889. Oxford at the Clarendon Press

This is a full-text PDF image facsimile version of the entire 700-plus pages of the original volumes.
August Weismann was one of the most influential biologists of the late nineteenth century. In Essays Upon Heredity he presents a series of essays giving his thoughts on the mechanisms of heredity. Two of the essays offer specific refutation of the idea that acquired characters can be inherited.

Evolution in Mendelian populations. Wright, Sewall 1931. Genetics, 16:97-159.

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Evolution in Mendelian populations. Wright, Sewall. 1931. Genetics, 16:97-159.

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Soon after the establishment of Mendelian genetics, several workers began to explore how Mendelian mechanisms would affect changes in gene frequencies in populations - that is, they began to explore the implications of Mendelism for evolution.

Sewall Wright became one of the leading theoreticians who studied Mendelism in the context of population genetics. This paper is a key presentation of his thinking on how Mendelism and evolution might interact.

Experimental Studies in the Physiology of Heredity. Bateson, William, Saunders, E. R., and Punnett, R. C. 1904. Reports to the Evolution Committee of the Royal Society, II, 1904, pp. 1-131

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William Bateson was the first English-speaking scientist to appreciate the potential significance of Mendel's work. He and his co-workers began immediately to confirm and extend Mendel's findings. This report to the evolution committee of the Royal Society represents one of the very first systematic investigations into Mendelism as a possible general explanation for the fundamental mechanisms of heredity.

Experiments in plant hybridization. Mendel, Gregor. 1865. Verhandlungen des naturforschenden Vereines in Brünn, Bd. IV für das Jahr 1865, Abhandlungen, 3-47.

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For those wishing to see and read Mendel in the original, this provides an image facsimile of the original paper as it was published in German.

This version is in Adobe PDF format, but the pages are images of the original publication, not a new type-setting of the material. This is a large file (2,142,414 bytes).

Experiments in plant hybridization. Mendel, Gregor. 1865. Verhandlungen des naturforschenden Vereines in Brünn, Bd. IV für das Jahr 1865, Abhandlungen, 3-47.

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In February and March of 1865, Gregor Mendel presented the Brünn Natural History Society in Brünn, Czechoslovakia, with the results of his investigations into the mechanisms governing inheritance in pea plants. The next year, the work was published as Mendel, Gregor. 1866. "Versuche über Pflanzen Hybriden." Verhandlungen des naturforschenden Vereines in Brünn, 4:3-47.

In this remarkable paper, Mendel laid the groundwork for later became the science of genetics. However, the work was largely ignored when it appeared and Mendel moved on to other things. He died in 1884.

His work was rediscovered at the turn of the century and its significance immediately recognized. Genetics, as a formal scientific discipline, exploded into activity in 1900.

An annotated version of Mendel's paper is also available. The annotated version contains explanatory notes throughout the document. This can be useful to those reading Mendel's paper for the first time.

For those wishing to see and read Mendel in the original, a facsimile reprint edition is available. This version is in Adobe PDF format, but the pages are images of the original publication, not a new type-setting of the material. This is a large file (2,142,414 bytes).

You may also with to visit The Mendel Web site, maintained at NETSPACE.ORG by Roger Blumberg. A MIRROR SITE of MendelWeb is maintained at the University of Washington. The site offers many additional resources for the Mendel scholar.

Experiments with Poultry. Hurst, C. C. 1904. Reports to the Evolution Committee of the Royal Society, II, 1904, pp. 131-154

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William Bateson was the first English-speaking scientist to appreciate the potential significance of Mendel's work. He and his co-workers began immediately to confirm and extend Mendel's findings. C. C. Hurst was one of Wm Bateson's early co-workers. This report to the evolution committee of the Royal Society represents one of the very first systematic investigations into Mendelism as a possible general explanation for the fundamental mechanisms of heredity.

Factors and Unit Characters in Mendelian Heredity. Morgan, Thomas H. 1913. The American Naturalist, 47:5-16.

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G. Mendel's law concerning the behavior of progeny of varietal hybrids. Correns, Carl 1900. First published in English as: Correns, C., 1950. G. Mendel's law concerning the behavior of progeny of varietal hybrids. Genetics, 35(5, pt 2): 33-41. Originally published as: Correns, C. 1900. G. Mendels Regel über das Verhalten der Nachkommenschaft der Rassenbastarde. Berichte der Deutschen Botanischen Gesellschaft, 18: 158-168.

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Correns, along with Hugo de Vries and Erik von Tschermak, is considered to be one of the three co-discovers of Mendel's work in 1900. Correns was the only one of the three to acknowledge Mendel in the title of his paper. Correns' paper begins:

The latest publication of Hugo de Vries: Sur la loi de disjonction des hybrides, which through the courtesy of the author reached me yesterday, prompts me to make the following statement: In my hybridization experiments with varieties of maize and peas, I have come to the same results as de Vries, who experimented with varieties of many different kinds of plants, among them two varieties of maize. When I discovered the regularity of the phenomena, and the explanation thereof - to which I shall return presently - the same thing happened to me which now seems to be happening to de Vries: I thought that I had found something new. But then I convinced myself that the Abbot Gregor Mendel in Brünn, had, during the sixties, not only obtained the same result through extensive experiments with peas, which lasted for many years, as did de Vries and I, but had also given exactly the same explanation, as far as that was possible in 1866.

Galton and Mendel: Their contribution to genetics and their influence on biology. Harris, J. Arthur 1923. The Scientific Monthly, 16: 247-263.

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In December of 1922, the American Society of Naturalists held a special session to honor the centenaries of the birth of Gregor Mendel and of Francis Galton. This is one of the four papers presented at that session and later published in the The Scientific Monthly.

Genetic Definitions in the New Standard Dictionary. Shull, G. H. 1915. The American Naturalist, 49:52-59.

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In this short paper, Shull takes exception to some recently published dictionary definitions of many technical genetics terms and he offers corrected definitions in their stead. The main value of this paper to modern readers is that it gives a very good idea of what geneticists (or at least this geneticist) meant by their use of genetic terminology at the time. Although many of Shull's proffered definitions would be at home in a modern biology text, some are no longer in current usage.

Shull could have done a better job of defining "alternative inheritance" by adding "contrast with continuous inheritance," since at the time of his writing there was still a school of thought that argued that most heritable variation was continuous but that Mendelian theories provided explanations only for cases of "alternative inheritance," which were rare in nature and might only represent artifacts of inheritance in domesticated organisms.

For just such a criticism of alternative inheritance, see Weldon, W. F. R. 1902 Mendel's laws of alternative inheritance in peas. Biometrika, 1:228-254, soon to be republished by the Electronic Scholarly Publishing project.

Genetic studies on Drosophila simulans. I. Introduction. Hybrids with Drosophila melanogaster. Sturtevant, Alfred H. 1920. Genetics, 5:488-500.

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Genetic studies on Drosophila simulans. II. Sex-linked groups of genes. Sturtevant, Alfred H. 1921. Genetics, 6:43-64.

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Genetic studies on Drosophila simulans. III. Autosomal genes. General discussion. Sturtevant, Alfred H. 1921. Genetics, 6:179-207.

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Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors.. Muller, Hermann J. 1918. Genetics, 3:422-499.

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Genetical and cytological studies of a deficiency (notopleural) in the second chromosome of Drosophila melanogaster. Bridges, Calvin B., Skoog, Eleanor Nichols, and Li, Ju-chi. 1936. Genetics, 21:788-795.

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Gregor Mendel's letters to Carl Nägeli, 1866-1873. Mendel, Gregor 1866-1873. First published in English as: Mendel, G. 1950. Gregor Mendel's Letters to Carl Nägeli. Genetics, 35(5, pt 2): 1-29. Originally published as: Abhandlungen der Mathematisch-Physischen Klasse der Königlich Sächsischen Gesellschaft der Wissenschaften 29: 189-265, 1905. Reprinted in "Carl Correns, Gesammelte Abhandlungen zur Vererbungswissenschaft aus periodischen Schriften" 1899-1924. (Fritz V. Wettstein ed.) Berlin, Julius Springer, 1924. pp. 1237-1281.

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After his original paper on peas, Mendel published only one other paper on genetics, that one on Hieracium. These letters to Nägeli provide a rare additional glimpse into Mendel's thinking as he pursued his investigations on heredity.

Heredity in Relation to Evolution and Animal Breeding. Castle, W. E. 1911. New York: D. Appleton and Company

This is an image facsimile version of the entire 184-page original edition.

Heredity in the Light of Recent Research. Doncaster, L. 1911. Cambridge: University Press

This is an image facsimile version of the entire 144-page original first edition.

Heredity. Thomson, J. Arthur. 1908. London: John Murray

This is a PDF image facsimile version of the entire 596-page original first edition.
This book is one of the first textbook treatments of heredity after the rediscovery of Mendel's work. Thomson provides his analysis in the context of the understanding of inheritance in the pre-Mendelian late nineteenth century. Chapter 11, History of Theories of Heredity and Inheritance summarizes many of the nineteenth-century theories of heredity.

In his bibliography, Thomson cites many nineteenth-century works. He also provides a subject-index to the bibliography, making this collection of citations especially valuable.

Hybridisation and cross-breeding as a method of scientific investigation. Bateson, William. 1899. Journal of the Royal Horticultural Society, 24:59-66.

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In this talk, given in 1899, before Mendel's work had been rediscovered, Bateson gives his vision of what kind of research will be necessary to shed light on the processes of inheritance and evolution:

What we first require is to know what happens when a variety is crossed with its nearest allies. If the result is to have a scientific value, it is almost absolutely necessary that the offspring of such crossing should then be examined statistically. It must be recorded how many of the offspring resembled each parent and how many shewed characters intermediate between those of the parents. If the parents differ in several characters, the offspring must be examined statistically, and marshalled, as it is called, in respect of each of those characters separately.

One would be hard pressed to provide a better anticipation of the experimental approach of Gregor Mendel. Small wonder that Bateson, upon encountering Mendel's work, quickly became convinced that the correct method for studying inheritance was finally at hand.

Inborn Errors of Metabolism, Second Edition. Garrod, Archibald. 1923. London: Henry Frowde and Hodder & Stoughton

This is a full-text PDF image facsimile version of the entire 216-page original book.
Less than two years after the rediscovery of Mendelism and just a few years after the word biochemistry was first coined, Garrod reported on alkaptonuria in humans and came to the conclusion that it was inherited as a Mendelian recessive and that the occurrence of mutations (sports in the word of the time) in metabolic function should be no more surprising than inherited variations in morphology.

In 1908, he summarized his thinking about "inborn errors of metabolism" (his term for what we would now think of as mutations in genes affecting metabolic function) in a book. An image facsimile of the second edition (1923) of that book is presented here.

Like Mendel's work, Garrod's insights were so far ahead of their time that his entire work on metabolic mutations was largely neglected, until later efforts to elucidate the physiological functioning of genes led to the Nobel-prize-winning one-gene, one-enzyme hypothesis.

Inheritance of the direction of coiling in Limnaea. Sturtevant, Alfred H. 1923. Science, 58:269-270.

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As evidence mounted for the chromosomal basis of inheritance, occasional examples were discovered that seemed to challenge the Mendelian model, as mapped to the chromosomes by T. H, Morgan and his students. In this paper, A. H. Sturtevant (one of Morgan’s students) shows that apparently aberrant patterns of inheritance can be seen to correspond to the Mendelian model, if care is taken to assign phenotype to the correct individual.

The case in question is the direction of shell coiling in snails of the genus Limnaea. These shells can either coil to the right (dextral) or left (sinistral). Coiling seemed to be an inherited trait, except that the observed patterns of inheritance were strange. Broods of offspring from sinistral snails, produced by self-fertilization (these snails are hermaphroditic) were either all sinistral or all dextral (never some of each). The same was found true if the single parent was dextral. Complicated models had been offered to explain these results, but here Sturtevant shows that a much simpler model is equally effective:

An analysis ?£ the data presented suggests that the case is a simple Mendelian one, with the dextral character dominant, but with the nature of a given individual determined, not by its own constitution but by that of the unreduced egg from which it arose.

A similar problem exists with the color of bird eggs. Chickens, for example, can produce eggs that are either brown or white, and these colors are genetically determined. However, the trait “shell color” is an attribute of the hen laying the eggs, not of the chick that hatches out of the egg. When you realize that the shell is created as a secretion in the hen’s oviducts, this makes perfect sense, even though the actual egg shell is ultimately separate from the body of the hen and is part of the egg from which the chick hatches.

The direction of shell coiling is now known to be controlled by specific proteins present in the cytoplasm of the egg. These proteins are produced early in egg development, prior to fertilization, and so are produced solely from genes present in the mother. Just as with the color of egg shells in chickens, the direction of shell coiling in Limnaea is really part of the phenotype of the mother of the snail, not of the snail actually wearing the shell.

Intracellular Pangenesis. Vries, Hugo de. 1910. Chicago: The Open Court Publishing Co.

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This classic work, first published in German in 1889, presents De Vries's theory of the pangen, a morphological structure carrying hereditary material. The name "gene," later coined by Johannsen, was derived from de Vries's pangen.

Hugo De Vries is often now remembered, along with Correns and von Tschermak, primarily for their role in the rediscovery of Mendel in 1900. Of the three, however, De Vries was by far the most established scientist. He was one of the most well-known botanists in Europe and had already been developing his own theoretical model of heredity - intracellular pangenesis.

Intracellular pangenesis was based on Darwins's concept of pangenesis as presented in chapter 27 of his massive, two-volume The Variation of Animals and Plants under Domestication. De Vries view, however, has a more modern feel than Darwin's, as De Vries thought about the inheritance of individual characters (as did Mendel), not just about more general overall species characteristics. De Vries called his units of inheritance pangens and later he came to believe that a pangen for a particular trait was the same, no matter in which species it occurred. This is an interesting anticipation of what would later be seen as genetic homology.

Is the arrangement of the genes in the chromosome linear? Castle, W.E. 1919. Proceedings of the National Academy of Sciences, 5:25-32.

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Materials for the Study of Variation. Bateson, William. 1894. London: Macmillan and Company.

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William Bateson was the first English-speaking scientist to recognize the significance of Mendel's work. Before the rediscovery of Mendel's work in 1900, Bateson had been active in studying morphology, with a special interest in discontinuous variation as it might apply to the origin of species.

In this book Bateson summarizes his observations on discontinuous variation. His concern for this kind of variation probably contributed greatly to the quickness with which he grasped the significance of Mendel's work.

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Mendel and his contemporaries. East, E. M. 1923. The Scientific Monthly, 16: 225-237.

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In December of 1922, the American Society of Naturalists held a special session to honor the centenaries of the birth of Gregor Mendel and of Francis Galton. This is one of the four papers presented at that session and later published in the The Scientific Monthly.

Mendel's Principles of Heredity: A Defence. Bateson, William. 1902. London: Cambridge University Press.

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William Bateson was the first English-speaking scientist to recognize the significance of Mendel's work. In an 1899 paper, he had anticipated the sort of experimental design that Mendel used, and in 1900, shortly after Mendel's rediscovery, he published another paper in which he summarized Mendel's work in English, declaring it to be "a new principle of the highest importance."

In the present work, Bateson offers a book-length presentation of Mendel's approach to genetic research, including the first English translation of both Mendel's work on peas and his later work on Hieracium. The book is subtitled A Defence because the Mendelian approach to genetics was initially strongly resisted by the biometrician school, which based their thinking on Galton's ancestral law of heredity.

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Mendel's laws of alternative inheritance in peas. Weldon, W. F. R. 1902. Biometrika, 1:228-254.

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Textbook treatments of genetics often give the impression that upon being rediscovered Mendel's dominated the field. This is not so. Galton and his followers had been working for decades studying patterns of inheritance and had developed a formal quantitative model for the inheritance of "natural" (i.e., continuous) traits.

The biometricians, as they were called, felt that Mendel's work was a limited assessment, valid only when applied to discontinuous traits in domesticated species. Weldon was a leading proponent of the biometrician school. This paper provides a strong summary of why the biometricians believed Mendel's work to be fundamentally flawed and of no general consequence. The paper concludes:

The fundamental mistake which vitiates all work based upon Mendel's method is the neglect of ancestry, and the attempt to regard the whole effect upon offspring, produced by a particular parent, as due to the existence in the parent of particular structural characters; while the contradictory results obtained by those who have observed the offspring of parents apparently identical in certain characters show clearly enough that not only the parents themselves, but their race, that is their ancestry, must be taken into account before the result of pairing them can be predicted.

Mendel's principles of heredity and the maturation of the germ cells. Wilson, Edmund B. 1902. Science, NS 16: 991-993.

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In this short note, E. B. Wilson calls attention to the possible relationship between Mendelian patterns of inheritance and the assortment of chromosomes in meiosis.

Mendelian Proportions in a Mixed Population. Hardy, G. H. 1908. Science, NS. XXVIII:49-50.

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Every geneticist has heard of the Hardy-Weinberg Law and of Hardy-Weinberg Equilibrium, and nearly all basic biology texts teach that G. H. Hardy played a seminal role in founding population genetics. But, what most biologists don't realize is that Hardy's total contribution to biology consisted of a single 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.

Mendelism, 1st Edition. Punnett, R. C. 1905. Cambridge: Bowes and Bowes

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This little book is the first edition of the first genetics textbook ever written. It was published just five years after Mendel's work was rediscovered.

Mendelism, 2nd Edition. Punnett, R. C. 1907. Cambridge: Bowes and Bowes

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This second edition of Punnett's text on Mendelism came out just two years after the first edition. In this new edition, Punnett Squares appeared for the first time. Also, the author included an index (that could fit on a single page with room left over).

Mutant races derived from Oenothera lamarckiana semigigas. Vries, Hugo de 1925. Genetics, 10:211-222.

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Mutations of Oenothera suaveolens desf. Vries, Hugo de 1918. Genetics, 3:1-26.

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Mutations of bacteria from virus sensitivity to virus resistance. Luria, S. E., and Delbrück, M. 1943. Genetics, 28:491-511

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This classic paper is the "fluctuation test" in which Luria and Delbrü first demonstrated the occurrence of microbial genetics. In fact, the fluctuation test must be regarded as the founding of bacterial genetics since it gave the first real proof that bacteria both possessed genes and experienced mutation. Luria and Delbrück shared the 1969 Nobel Prize with Alfred Hershey.

Luria and Delbrück were also able to use their data to calculate the actual mutation rate per bacterial cell division. Averaged across all of their experiments, this came to approximately 2.45 x 10^-8. Thus, they not only proved that true genetic mutations occurred in bacteria, but also that such mutations were just as rare in bacteria as they were in higher organisms. Their work demonstrated that heritable variation in bacteria could be attributed to mechanisms similar to those in higher organisms. The previously puzzling ability of bacteria to respond rapidly and adaptively to changes in the environment could now be recognized as nothing more than the normal consequence of random gene mutation, followed by selection, in huge, rapidly reproducing populations.

Following this discovery, many researchers hurried to determine the range of true genetic mutation occurring in bacteria. Soon, such variation was detected in virtually every trait that could be studied, such as color, colony morphology, virulence (ability to infect a host), resistance to antimicrobial agents, nutritional requirements, and fermentation abilities (i.e., the ability to use different compounds as carbon sources).

Natural Inheritance. Galton, Francis 1889. London: Macmillan

This is an image facsimile version of the entire 260-page original first edition.

Non-disjunction as proof of the chromosome theory of heredity (part 1). Bridges, Calvin B. 1916. Genetics, B, 1:1-52.

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This paper was published as the first article in the first volume the new journal genetics. As the title states, the paper offered PROOF that genes are real, physical things that are carried on chromosomes.

This article was scanned from Alfred Sturtevant's personal copy of Genetics. Access to the journal was provided by Edward B. Lewis and Elliot M. Meyerowitz of the California Institute of Technology.

Non-disjunction as proof of the chromosome theory of heredity (part 2). Bridges, Calvin B. 1916. Genetics, B, 1:107-163.

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This paper was published as the first article in the first volume the new journal genetics. As the title states, the paper offered PROOF that genes are real, physical things that are carried on chromosomes.

This article was scanned from Alfred Sturtevant's personal copy of Genetics. Access to the journal was provided by Edward B. Lewis and Elliot M. Meyerowitz of the California Institute of Technology.

Notes on the accessory chromosome. McClung, C. E. 1901. Anatomischer Anzeiger, 20:220-226.

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In this brief paper, McClung introduces the evidence that male and female insects exhibit different chromosomal structures in their nuclei and that spermatozoa fall into two types - those that carry the "accessory chromosome" and those that do not.

Based on this analysis, McClung suggests that the presence or absence of the "accessory chromosome" in spermatozoa may determine the sex of the progeny. McClung published this short note in 1901 to alert the scientific community of his findings and to alert them to a more detailed argument that he had already submitted for publication elsewhere and that he knew would appear a year later, in McClung, C. E. 1902. The accessory chromosome - Sex determinant?. Biological Bulletin, 3:43-84.

On Hieracium-hybrids obtained by artificial fertilisation. Mendel, Gregor 1869. Verhandlungen des naturforschenden Vereines, Abhandlungen, Brünn, Bd. VIII für das Jahr 1869, 26-31. (Translated and reprinted as an appendix to Bateson, W. 1909. Mendel's Principles of Heredity. Cambridge University Press.)

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After his original paper on peas, Mendel published only one other paper on genetics, this one on Hieracium. Unknown to Mendel, Hieracium does not experience normal sexual fertilization, making it impossible for him to confirm the findings that he had obtained earler with peas.

On a modified Mendelian ratio among yellow mice. Castle, W. E., and Little, C. C. 1910. Science, N.S., 32:868-870.

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Here, Castle and Little offer evidence consistent with the idea that the gene for yellow fur in mice, studied earlier by Cuénot, is probably lethal when carried homozygously.

On the Generation of Animals. Aristotle. 350 BC.

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Any collection of critical works in the history of biology must include works by Aristotle. Here, in On the Parts of Animals, Aristotle provides one of the world's first efforts to understand life in terms of its component parts.

On the Natural Faculties. Galen. 170 AD.

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Galen was perhaps the last significant scholar of biology before the onset of the dark ages. Although his analysis (see below) seems odd from a modern perspective, nonetheless he is addressing some of the fundamental problems of heredity and development - how does life begin and how does it grow and develop?

Let us speak then, in the first place, of Genesis, which, as we have said, results from alteration together with shaping. The seed having been cast into the womb or into the earth (for there is no difference), then, after a certain definite period, a great number of parts become constituted in the substance which is being generated; these differ as regards moisture, dryness, coldness and warmth, and in all the other qualities which naturally derive therefrom.

On the Origin of Species. Darwin, C. 1859. London: John Murray, Albemarle Street.

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This is the book that changed the world and defined modern biology. By making mechanisms of heritable variation central to the biggest issue in all of biology, Darwin initiated the genetics revolution.

On the Parts of Animals. Aristotle. 350 BC.

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Any collection of critical works in the history of biology must include works by Aristotle. Here, in On the Parts of Animals, Aristotle provides one of the world's first efforts to understand life in terms of its component parts.

On the distribution of mutant characters among the chromosomes of Oenothera lamarckiana. Vries, Hugo de, and Boedijn, K. 1923. Genetics, 8:233-238.

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On the law which has regulated the introduction of new species. Wallace. A. R. 1855. Annals and Magazine of Natural History, 2nd Series. 16:184-196.

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Today Darwin's name is known to everyone, while Alfred Russel Wallace is familiar to only a few. Yet the concept of evolution by natural selection was independently developed by Wallace and Darwin, with Wallace publishing first. This paper, and the 1858 manuscript he sent directly to Darwin, show clearly that, prior to Darwin's publication, Wallace had a firm grasp on the concept of evolution.

On the morphology of the chromosome group in Brachystola magna. Sutton, Walter S. 1902. Biological Bulletin, 4:24-39.

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In this paper, Sutton reports cytological studies of grasshopper chromosomes that lead him to conclude 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.

After presenting considerable evidence for his assertions, Sutton closes his paper with a sly reference to its undoubted significance:

I may finally call attention to the probability that the association of paternal and maternal chromosomes in pairs and their subsequent separation during the reducing division as indicated above may constitute the physical basis of the Mendelian law of heredity. To this subject I hope soon to return in another place.

On the nature of size factors. Wright, Sewall 1918. Genetics, 3:367-374.

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Problems of heredity as a subject for horticultural investigation. Bateson, William. 1900. Journal of the Royal Horticultural Society, 25:54-61.

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Mendel's work of 1865 was largely neglected, until 1900 when it was simultaneously rediscovered by Hugo de Vries, Carl Correns, and Erik von Tschermak. When Mendel's work came to the attention of William Bateson (who himself had already been advocating controlled crosses as an approach to studying heredity), he was convinced that Mendel's work was of major importance:

That we are in the presence of a new principle of the highest importance is, I think, manifest. To what further conclusions it may lead us cannot yet be foretold.

Bateson devoted the remainder of his scientific career to further elucidations of "Mendelism." This present paper captures the enthusiasm of Bateson's first encounter with the works of Mendel.

Proceedings of the Sixth International Congress of Genetics, Vol. I. Jones, Donald F. (ed) 1932. Austin, Texas: Genetics Society of America

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The Proceedings of the Sixth International Congress of Genetics, held in 1932, offers a glimpse into classical genetics at the height of its power and influence. Thomas Morgan, who had just received the first Nobel Prize ever awarded in genetics, served as president of the congress.

The participants list reads like a who's who of classical genetics: The three rediscovers of Mendel - Correns, de Vries, and von Tschermak - all attended the meeting. Morgan, Sturtevant, and Muller gave talks. Population genetics and the relationship of genetics to evolution was discussed by R. A. Fisher, J. B. S. Haldane, and Sewall Wright.

According to the Treasurer's Report, the total cost of the meeting was $17,583.58.

Random segregation versus coupling in Mendelian inheritance Morgan, Thomas H. 1911. Science, 34:384.

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Sex-limited inheritance in Drosophila. Morgan, Thomas H. 1910. Science, 32:120-122.

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After Mendel's work was rediscovered in 1900, many researchers worked to confirm and extend his findings. Although a possible relationship between genes and chromosomes was suggested almost immediately, proof of that relationship, or even evidence that genes were physical objects, remained elusive. To many, the gene served only as a theoretical construct, conveniently invoked to explain observed inheritance patterns. In 1909, Morgan himself published a paper in which he expressed his skepticism about the facility with which Mendelian explanations were adjusted to fit the facts.

Just one year later, however, Morgan published the results of his work on an atypical male fruit fly that appeared in his laboratory, and all this began to change. Normally Drosophila melanogaster have red eyes, but Morgan's new fly had white eyes. The inheritance pattern for this new eye-color trait suggested strongly that the gene for eye-color was physically attached to the X-chromosome. In the paper, Morgan concluded:

It now becomes evident why we found it necessary to assume a coupling of [the eye-color gene] and X in one of the spermatozoa of the red-eyed F1 hybrid. The fact is that this R and X are combined, and have never existed apart.

In this present paper, Morgan offered the first evidence that genes are real, physical objects, located on chromosomes, with properties that could be manipulated and studied experimentally. The white-eyed fly provided the foundation upon which Morgan and his students established the modern theory of the gene.

Simplicity versus adequacy in Mendelian formulae Morgan, Thomas H. 1913. The American Naturalist, 47:372-374

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Soon after Mendel was rediscovered, the nature of the gene was being worked out. Along the way, many suggested changes to the symbology being used (e.g., B for dominant allele, b for recessive). Here Morgan offers some thoughs on changing Mendelian symbols.

Simplification of Mendelian formulae. Castle, W. E. 1913. The American Naturalist, 47:170-182

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Soon after Mendel was rediscovered, the nature of the gene was being worked out. Along the way, many suggested changes to the symbology being used (e.g., B for dominant allele, b for recessive). Here Castle offers some suggestions for changing Mendelian symbols.

Studies in Spermatogenesis Part II., A comparative study of the heterochromosomes in certain species of coleoptera, hemiptera and lepidoptera, with especial reference to sex determination. Stevens, Nettie M. 1906. Carnegie Institution of Washington, Publication No. 36, part II., pp 1-43.

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Studies in Spermatogenesis with especial reference to the "accessory chromosome". Stevens, Nettie M. 1905. Carnegie Institution of Washington, Publication No. 36., pp 1-33.

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Studies on the germ cells of aphids. Stevens, Nettie M. 1906. Carnegie Institution of Washington, Publication No. 51., pp 1-28.

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Systems of mating. I. The biometric relations between parent and offspring. Wright, Sewall 1921. Genetics, 6:111-123.

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Systems of mating. II. The effects of inbreeding on the genetic composition of a population. Wright, Sewall 1921. Genetics, 6:124-143.

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Systems of mating. III. Assortative mating based on somatic resemblance. Wright, Sewall 1921. Genetics, 6:144-161.

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Systems of mating. IV. The effects of selection. Wright, Sewall 1921. Genetics, 6:162-166.

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Systems of mating. V. General considerations. Wright, Sewall 1921. Genetics, 6:167-178.

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Ten Years of Heredity. Shull, A. Franklin 1922. Transactions of the American Microscopical Society, 41:82-100.

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The "Presence and Absence" Hypothesis. Shull, George Harrison 1909. The American Naturalist, 43:410-419.

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The Birth of Genetics Mendel - de Vries - Correns - Tschermak 1950. Special supplement to the journal Genetics 35(5, pt 2): 1-48.

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To celebrate the fiftieth anniversary of the rediscovery of Mendel's work, the Genetics Society of America published this special supplement, containing translations of the original papers by the rediscovers of Mendel - Carl Correns, Erik von Tschermak, and Hugo de Vries. It also contains letters written by Mendel and sent to Carl N&aum;geli, a leading botanist.

This was the first time these key works were made available in English translation.

The Cell in Development and Inheritance, 2nd Edition Wilson, Edmund B. 1900. New York: The Macmillan Company

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Edmund B. Wilson was the leading cytologist of his time and The Cell in Development and Inheritance was the definitive text on cytology from 1896 into the 1930's. A modern reader will be surprised to see how many of the illustrations in the book seem familiar – versions of many of them still appear in textbooks of introductory biology.

The last chapter in the book is entitled "Theories of Inheritance and Development:, and it begins:

Every discussion of inheritance and development must take as its point of departure the fact that the germ is a single cell similar in its essential nature to any one of the tissue-cells of which the body is composed. That a cell can carry with it the sum total of the heritage of the species, that it can in the course of a few days or weeks give rise to a mollusk or a man, is the greatest marvel of biological science. In attempting to analyze the problems that it involves, we must from the outset hold fast to the fact, on which Huxley insisted, that the wonderful formative energy of the germ is not impressed upon it from without, but is inherent in the egg as a heritage from the parental life of which it was originally a part. The development of the embryo is nothing new. It involves no breach of continuity, and is but a continuation of the vital processes going on in the parental body. What gives development its marvellous character is the rapidity with which it proceeds and the diversity of the results attained in a span so brief.

But when we have grasped this cardinal fact, we have but focussed our instruments for a study of the real problem. How do the adult characteristics lie latent in the germ-cell; and how do they become patent as development proceeds? This is the final question that looms in the background of every investigation of the cell. In approaching it we may well make a frank confession of ignorance; for in spite of all that the microscope has revealed, we have not yet penetrated the mystery, and inheritance and development still remain in their fundamental aspects as great a riddle as they were to the Greeks. What we have gained is a tolerably precise acquaintance with the external aspects of development. The gross errors of the early preformationists have been dispelled.' We know that the germ-cell contains no predelineated embryo; that development is manifested, on the one hand, by the cleavage of the egg, on the other hand, by a process of differentiation, through which the products of cleavage gradually assume diverse forms and functions, and so accomplish a physiological division of labour. We can clearly recognize the fact that these processes fall in the same category as those that take place in the tissue-cells; for the cleavage of the ovum is a form of mitotic cell-division, while, as many eminent naturalists have perceived, differentiation is nearly related to growth and has its root in the phenomena of nutrition and metabolism. The real problem of development is the orderly sequence and correlation of these phenomena toward a typical result. We cannot escape the conclusion that this is the outcome of the organization of the germ-cells; but the nature of that which, for lack of a better term, we call "organization," is and doubtless long will remain almost wholly in the dark.

The Centenary of Gregor Mendel and of Francis Galton. East - Morgan - Harris - Shull 1923. The Scientific Monthly, 16: 225-270.

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In December of 1922, the American Society of Naturalists held a special session to honor the centenaries of the birth of Gregor Mendel and of Francis Galton. This is the collection of the four papers presented at that session and later published in the The Scientific Monthly.

The Constitution of the Hereditary Material. Morgan, Thomas H. 1915. Proceedings of the American Philosophical Society, 54:143-153.

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The Germ-Plasm. Weismann, August 1893. New York: Charles Scribner's Sons

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August Weismann was one of the most influential biologists of the late nineteenth century. In The Germ-Plasm he lays out a new theory of heredity, one based on the continuity of the germ-plasm (the gametes and the cells that give rise to the gametes) as opposed to the finite existence of the soma (the cells of the body).

Weismann introduces his book modestly:

Any attempt at the present time to work out a theory of heredity in detail may appear to many premature, and almost presumptuous: I confess there have been times when it has seemed so even to myself. I could not, however, resist the temptation to endeavour to penetrate the mystery of this most marvellous and complex chapter of life as far as my own ability and the present state of our knowledge permitted.

A key point in his theory is that it makes impossible the inheritance of acquired characteristics, and thus deals a death blow to Lamarckism, as well as to Darwin's pangenesis:

What first struck me when I began seriously to consider the problem of heredity, some ten years ago, was the necessity for assuming the existence of a special organised and living hereditary substance, which in all multicellular organisms, unlike the substance composing the perishable body of the individual, is transmitted from generation to generation. This is the theory of the continuity of the germ-plasm. My conclusions led me to doubt the usually accepted view of the transmission of variations acquired by the body (soma); and further research, combined with experiments, tended more and more to strengthen my conviction that in point of fact no such transmission occurs.

The History of Animals. Aristotle. 350 BC.

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Any collection of critical works in the history of biology must include works by Aristotle. Here, in The History of Animals, Aristotle provides a discussion of the diversity of life, with considerable attention to reproduction and heredity.

The Law of Heredity, Second Edition. Brooks, W. K. 1883. Baltimore and New York: John Murphy & Co., Publishers.

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It is often thought that, besides Mendel, little work on heredity occurred during the 19th Century. This is far from true. Darwin's Origin of Species placed the study of inherited variation at the center of biological thought. As this work by Brooks attests, considerable effort was made to understand heredity, especially as it related to natural selection.

Although the details of Brooks' analysis are now outdated, the book provides general insights into late-nineteenth Century thinking on heredity. Since Brooks was one of T. H. Morgan's instructors when Morgan was a student at Johns Hopkins, the book also provides insights into the specific instruction on heredity that was presented to the man who became the first recipient of a Nobel Prize for work on genetics.

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The Mechanism of Crossing-over. Muller, Hermann J. 1916. New York: The American Naturalist

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Beginning 1910, T. H. Morgan and his students established the foundations of modern genetics by making genes real - not theoretical entities.

This work is a collection of papers that represented the doctoral dissertation of one of those students - H. J. Muller.

The Mechanism of Mendelian Heredity. Morgan, Thomas H., Sturtevant, A. H., Muller, H. J., and C. B. Bridges 1915. New York: Henry Holt and Company

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This book, by T. H. Morgan and his students, is the first work to articulate a comprehensive, mechanistic model to explain Mendelian patterns of inheritance.

Although Mendelism had quickly been accepted as a good phenomenological explanation for the patterns seen in Mendelian crosses, until the work of Morgan's group, it was still possible to consider Mendelism to be a purely theoretical model of heredity. As Morgan's group first established the relationship of genes to chromosomes, then developed the first genetic map, and went on to describe a variety of interactions between chromosomes and Mendelian factors, the conclusions they offered became inescapable - genes are physical objects, carried on chromosomes in static locations.

Morgan's group made genes real and this book is the first full-length presentation of their findings. It revolutionized the study of heredity.

The Methods and Scope of Genetics. Bateson, William. 1908. London: Cambridge University Press.

This is a newly typeset full-text version of the entire 49-page original first edition.
This short book is a copy of the Inaugeral Address, given by Bateson upon the creation of the Professorship of Biology at Cambridge. In his introduction, Bateson notes:

The Professorship of Biology was founded in 1908 for a period of five years partly by the generosity of an anonymous benefactor, and partly by the University of Cambridge. The object of the endowment was the promotion of inquiries into the physiology of Heredity and Variation, a study now spoken of as Genetics.

It is now recognized that the progress of such inquiries will chiefly be accomplished by the application of experimental methods, especially those which Mendel’s discovery has suggested. The purpose of this inaugural lecture is to describe the outlook over this field of research in a manner intelligible to students of other parts of knowledge.

Here then is a view of how one of the very first practitioners of genetics conceived of the "Methods and Scope of Genetics".

The Morphology of the X Chromosome in Salivary Glands of Drosophila melanogaster and a New Type of Chromosome Map for this Element. Painter, Theophilus S. 1934. Genetics, 19: 448-469.

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