Mendelism: from hybrids and trade to a science

In this paper I explore the historical context in which news of the rediscovery of Mendel's laws was received in England. This exploration leads me to the Cambridge zoologist, William Bateson, to his exploitation of the prestige and support of the Royal Horticultural Society, and to his interaction with certain of the leading horticultural tradesmen prominent in that society. I argue that the policy of the RHS in the 1890s to promote hybridisation rather than plant collecting was of crucial importance in bringing about a productive symbiosis between Bateson and his circle and the horticultural community. I look for parallels between the aims of the horticulturists and the character of the Mendelian programme as it is represented in Bateson's foundational text: Mendel's Principles of Heredity (1909).     

The reception of Mendelism in the United States, 1900-1930

Scholars have differed on the question of why Mendel's work was neglected between 1865 and 1900, and the (by contrast) relatively rapid acceptance of Mendelism in many countries after 1900. This paper focuses on two factors that have not been well explored in the debate. The first is that Mendelism fit perfectly into the atomistic philosophy associated with mechanistic materialism in western science, and thus was strongly promoted by a younger group of biologists around 1900 to raise the prestige of biology to the rigorous level of the physical sciences. The second factor was that Mendelian theory, with its experimental and predictive qualities, fit well into the new demands for industrialization of agriculture both to feed a growing urban population and to provide an arena for capital expansion. This paper proposes that the early promotion of Mendelian research, by both private and public funds, owed as much to economic and social as to biological causes.     

Tschermak: a non-discoverer of mendelism. II. A critique

An examination of Tschermak's two papers of 1900 not only reinforces our conclusion cited in our first paper on Tschermak that he was not a rediscoverer of Mendelism, but also he did not understand Mendel when he had read it. His concept of dominance differed from that of Mendel, and his use of his own concept is inconsistent and contradictory. His discussion of his backcross data indicated that he had no idea of the nature of Mendelian ratios. Nowhere did he develop the ideas of segregation and independent assortment.     

Mendelism and medicine: controlling human inheritance in local contexts, 1920-1960

The rise of Mendelism has often been associated with the development of agricultural sciences and the attempts to improve varieties and select new plants. In contrast, historians have tended to stress the tensions between Mendelism and medicine originating in the influence of eugenicists. The use of Mendel's laws in the context of discussing human inheritance and the transmission of pathologies was nonetheless pervading the medical literature from the 1920s onwards. This paper investigates the dynamics of medical Mendelism by comparing developments in France and in Britain. In contrast to reluctant botanists and zoologists, the elite of the French medical profession was often 'Mendelian'. Mendel's laws have accordingly been integrated into a complex approach to the familial transmission of pathologies, into a theory of pathological inheritance, which combined genetics, germ theory and hygiene. This approach was widely accepted among the paediatricians and obstetricians active in both the eugenics movement and the natalist movement. The career of the pediatrician R. Turpin is a good example of the visibility of this form of medical Mendelism and of its long-lasting impact on genetic research in the country. In Britain, where the social basis of eugenics was not the medical profession, eugenics' claims often clashed with public health and hygiene priorities. Medical Mendelism was in the first place supported and advanced by doctors and scientists participating in the public debates about the care of 'feeble minded' and the classification of social groups. As revealed by the trajectory of L. Penrose this context favoured the linkage between statistics and pedigree analysis, thus leading to the 'Mendelization' of human pathologies. After the war, this Mendelization in turn facilitated the rise of medical genetics as a speciality focusing on genetic counselling and on the management of computable hereditary risks. This comparative analysis thus highlights: a) the influence of local medical cultures on the fate of Mendelism; b) the continuities between the pre-war studies of pathological inheritance and the post-war rise of medical genetics.     

What would have happened if Darwin had known Mendel (or Mendel's work)?

The question posed by the title is usually answered by saying that the "synthesis" between the theory of evolution by natural selection and classical genetics, which took place in 1930s-40s, would have taken place much earlier if Darwin had been aware of Mendel and his work. What is more, it nearly happened: it would have been enough if Darwin had cut the pages of the offprint of Mendel's work that was in his library and read them! Or, if Mendel had come across Darwin in London or paid him a visit at his house in the outskirts! (on occasion of Mendel's trip in 1862 to that city). The aim of the present paper is to provide elements for quite a different answer, based on further historical evidence, especially on Mendel's works, some of which mention Darwins's studies.     

The singular fate of genetics in the history of French biology, 1900–1940

In this study we have examined the reception of Mendelism in France from 1900 to 1940, and the place of some of the extra-Mendelian traditions of research that contributed to the development of genetics in France after World War II. Our major findings are:

Scientific animal breeding in Moravia before and after the rediscovery of Mendel's theory

Leading Moravian sheep breeders, who joined with university professors and other educated citizens to form a Sheep Breeders' Society in 1814, looked to science to provide a reliable basis for breeding. Their activities reached a climax in the 1830s, when they defined and focused on heredity as the central research goal. Among the members taking part was Abbot Cyrill F Napp, who in 1843 would accept Mendel into the monastery. The contributions of Abbot Napp to the sheep breeders' view of heredity are here described. After 1900, when Moravian animal breeding sought to embrace Mendelism, in competition with other theories, a major influence was exerted by Jaroslav Krízenecky (1896-1964). In 1963, Krízenecky accepted responsibility for establishing the Mendel Museum (Mendelianum) in Brno as a vehicle for historical research into the origin and essence of Mendel's discovery.     

Mach's phenomenalism and the British reception of Mendelism

The assimilation of Mendel's paper into Britain took place in an Edwardian social context. This paper concentrates on the interplay of empirical and philosophical issues in this reception. A feature of the British reception of mendelism, not duplicated elsewhere, was the role of phenomenalist philosophies of science as developed by the physicist-mathematician and scientific methodologist Karl Pearson from the philosophical positions of Austrian physicist Ernst Mach and British mathematician William Clifford. Pearson's philosophy of science forms the background to his subsequent collaboration with the zoologist W.F.R. Weldon. In this collaborative work, Pearson developed powerful statistical techniques for analyzing Weldon's empirical data on organic variation. Pearson's statistical analysis of causation and his rejection of hidden entities and causes in the explanation of evolutionary change formed the philosophical component of this program. The arguments of Pearson and Weldon were first brought to bear against the pre-Mendel 'discontinuist' analyses of variation of William Bateson. The introduction of Mendel's paper into these empirical and methodological debates consequently resulted in mathematically sophisticated attacks on Mendel's claims by Pearson and Weldon. This paper summarizes this history and argues for the creative importance of this biometrical resistance to Mendelism.     

Physics in the Galtonian sciences of heredity

Physics matters less than we once thought to the making of Mendel. But it matters more than we tend to recognize to the making of Mendelism. This paper charts the variety of ways in which diverse kinds of physics impinged upon the Galtonian tradition which formed Mendelism's matrix. The work of three Galtonians in particular is considered: Francis Galton himself, W. F. R. Weldon and William Bateson. One aim is to suggest that tracking influence from physics can bring into focus important but now little-remembered flexibilities in the Galtonian tradition. Another is to show by example why generalizations about what happens when 'physics' meets 'biology' require caution. Even for a single research tradition in Britain in the decades around 1900, these categories were large, containing multitudes.     

Role of de Vries in the rediscovery of Mendel's paper. II. Did de Vries really understand Mendel's paper?

In this paper, we discuss briefly three of the several lines of evidence that we believe demonstrate de Vries's lack of understanding of Mendel's paper. In our view, at least part of de Vries's failure of understanding derives from the fact that he appears to have viewed Mendel's paper as being mainly about the inheritance of characters that was his own interest. Therefore, he looked at it to see whether Mendel had found any laws of inheritance. Mendel had done his research for another purpose, to find the laws describing the formation of hybrids and the development of their offspring. Thus, de Vries started his examination of Mendel's paper with a very fundamental misunderstanding of what it was about.     

Mendel's experiments: A reinterpretation

Conclusion My conclusion is that Mendel deliberately, though without any real falsification, tried to suggest to his audience and readers an unlikely and substantially wrong reconstruction of the first and most important phase of his research. In my book I offer many reasons for this strange and surprising behavior,⁵³ but the main argument rests on the fact of linkage. Mendelian genetics cannot account for linkage because it was based on the idea of applying probability theory to the problem of species evolution. Central to the theory is the law of probability according to which the chance occurrence of a combination of independent events is the product of their separate probabilities. This is the common basis of Mendel's first and second laws, but this is why Mendel's second law on independent assortment is enunciated in too general a way. From Morgan's work we now know that characters may not always be independent if their genes are located very close one to the other on the same chromosome. And this was also the basis of Mendel's personal drama: he surely observed the effects of linkage, but he had no theoretical tools with which to explain it. So he presented his results in a logical structure consistent with the central idea of his theory. Had he described the real course of his experiments he would have had to admit that his law worked for only a few of the hundreds of Pisum characters — and it would thus have been considered more of an exception than a rule. This is why he insisted on the necessity of testing the law on other plants, and this is why in his second letter to Carl Nägeli he admits that the publication of his data was untimely and dangerous.⁵⁴.We can argue that already in 1866 Mendel was less confident that his so-called second law had the same general validity as the first — and that later he lost his confidence altogether. Contemporary testimony indicates that in the end he became as skeptical as all his contemporaries as to the scientific relevance of his theory.⁵⁵ But he was wrong. His research is in no way the fruit of methodological mistakes or forgery, and it remains a landmark in the history of science. He was only the victim of a strange destiny in which the use of probability theory was responsible, at the same time, for the strength and for the weakness of his theory. We must still consider him the father and founder of genetics.     

Mendelian inheritance in Germany between 1900 and 1910. The case of Carl Correns (1864-1933)

Carl Correns (1864-1933) came to recognize Mendel's rules between 1894 and 1900 while trying to find out the mechanism of xenia, that is, the direct influence of the fertilizing pollen on the mother plant in maize and peas among other species. In this paper, I am concerned with the ten years of Correns' work after the annus mirabilis of 1900 until 1910, when the main outlines of the new science of genetics had been established. It is generally assumed that after 1900 Correns quickly began probing the limits of Mendelian inheritance, both as far as the explanatory force of formal transmission genetics and the generality of Mendel's laws are concerned. A careful examination of his papers however shows that he was much more interested in the scope of Mendelian inheritance than in its limits. Even his work with variegated Mirabilis plants, which historiographical folklore still presents as a result of Correns' growing interest in cytoplasmic inheritance, can be shown to have been conducted to corroborate just the opposite, namely, the validity of the nuclear paradigm. The paper will show that Correns' research results in those years (among them the Mendelian inheritance of sex in higher plants) were the outcome of a complex experimental program which involved breeding experiments with dozens of different species.     

L. H. Bailey's citations to Gregor Mendel

L. H. Bailey cited Mendel's 1865 and 1869 papers in the bibliography that accompanied his 1892 paper, Cross-Breeding and Hybridizing, and Mendel is mentioned once in the 1895 edition of Bailey's "Plant-Breeding." Bailey claimed to have copied his 1892 references to Mendel from Focke. It seems, however, that while he may have first encountered references to Mendel's work in Focke, he actually copied them from the Royal Society "Catalogue of Scientific Papers." Bailey also saw a reference to Mendel's 1865 paper in Jackson's "Guide to the Literature of Botany." Bailey's 1895 mention of Mendel occurs in a passage he translated from Focke's "Die Pflanzen-Mischlinge."     

Marvelling at the Marvel: The Supposed Conversion of A.D. Darbishire to Mendelism

The so-called “biometric-Mendelian controversy” has received much attention from science studies scholars. This paper focuses on one scientist involved in this debate, Arthur Dukinfield Darbishire, who performed a series of hybridization experiments with mice beginning in 1901. Previous historical work on Darbishire’s experiments and his later attempt to reconcile Mendelian and biometric views describe Darbishire as eventually being “converted”' to Mendelism. I provide a new analysis of this episode in the context of Darbishire’s experimental results, his underlying epistemology, and his influence on the broader debate surrounding the rediscovery and acceptance of Mendelism. Iinvestigate various historiographical issues raised by this episode in order to reflect on the idea of “conversion” to a scientific theory. Darbishire was an influential figure who resisted strong forces compelling him to convert prematurely due to his requirements that the new theory account for particularly important anomalous facts and answer the most pressing questions in the field. This revised version was published online in July 2006 with corrections to the Cover Date.     

Appropriation and commercialization of the Pasteur anthrax vaccine

Whereas Pasteur patented the biotechnological processes that he invented between 1857 and 1873 in the agro-food domain, he did not file any patents on the artificial vaccine preparation processes that he subsequently developed. This absence of patents can probably be explained by the 1844 patent law in France that established the non-patentable status of pharmaceutical preparations and remedies, including those for use in veterinary medicine. Despite the absence of patents, the commercial exploitation of the anthrax vaccine in the 1880s and 1890s led to a technical and commercial monopoly by Pasteur's laboratory as well as the founding of a commercial company to diffuse the vaccine abroad. Pasteur repeatedly refused to transfer his know-how and anthrax vaccine production methods to foreign laboratories, on the grounds that he wished to control the quality of the vaccines produced. Indeed, it was relatively difficult to transfer a method that was not yet perfectly stabilized in the early 1880s. Pasteur also wanted to maintain the monopoly of his commercial company and to increase the profits from vaccine sales so that the Institut Pasteur could be financially independent. The 'Pasteur anthrax vaccine' operating licences are described and analysed in detail in this article.     

A.N. Kolmogorov's defence of Mendelism

In 1939 N.I. Ermolaeva published the results of an experiment which repeated parts of Mendel's classical experiments. On the basis of her experiment she concluded that Mendel's principle that self-pollination of hybrid plants gave rise to segregation proportions 3:1 was false. The great probability theorist A.N. Kolmogorov reviewed Ermolaeva's data using a test, now referred to as Kolmogorov's, or Kolmogorov-Smirnov, test, which he had proposed in 1933. He found, contrary to Ermolaeva, that her results clearly confirmed Mendel's principle. This paper shows that there were methodological flaws in Kolmogorov's statistical analysis and presents a substantially adjusted approach, which confirms his conclusions. Some historical commentary on the Lysenko-era background is given, to illuminate the relationship of the disciplines of genetics and statistics in the struggle against the prevailing politically-correct pseudoscience in the Soviet Union. There is a Brazilian connection through the person of Th. Dobzhansky.     

Genetics and the evolutionary process

Population genetics was put forward as a mathematical theory between 1918 and 1932 and played a leading part in the rediscovery of the concept of natural selection. As an autonomous science developing Mendel's laws at the population scale and a key element of the Darwinian theory of evolution, its dual status led its practioners to initially overlook some consequences of Mendelism not accounted for by the Darwinian theory, including random drift and the cost of selection. The latter were put forward on purely theoretical grounds in the 1950s, but their importance was acknowledged only when empirical data on protein evolution and enzyme polymorphism (since 1965) and on DNA variation (since 1983) were obtained. The neutralist/selectionist debate that ensued involved disagreement over the scientific method as well as over the mechanisms of molecular evolution. Population genetics has long assumed the existence of natural selection a priori. It has since recentred around the null hypothesis that molecular evolution is neutral. This new approach, applied to sequence comparison and to the study of linkage disequilibrium, is logically more justified, yet empirical observations derived from it paradoxically show the overwhelming importance of selective effects within genomes.     

No evolution,no heredity,just development—Julius Schaxel and the end of the Evo–Devo agenda in Jena, 1906–1933: a case study

Julius Schaxel is an almost forgotten figure in the history of early twentieth century biology. By focusing on his life and work, I would like to illustrate several central developments in that period of history of biology. Julius Schaxel was an early representative and organizer of theoretical biology, discussing and criticizing both Wilhelm Roux’s mechanism and Hans Driesch’s vitalism. In addition to his theoretical work, Schaxel also did experimental research on developmental issues to support his critique. In this paper, special emphasis is made on the negotiating practice of Schaxel, which he used to establish a new area of biological research and a new audience for that area. In contrast to these new fields, Schaxel can be also portrayed as the endpoint of a research tradition investigating ontogeny and phylogeny together, which today is called Evo–Devo. Following Garland Allen’s dialectical processes that led to the decline of the Evo–Devo research agenda, Schaxel’s example is used to investigate these processes.