A special role for the genotype? Some comments on Keith Baverstock: "The gene: An appraisal".

There is at present uneasiness about the conceptual basis of genetics. The gene concept has become blurred and there are problems with the distinction between genotype and phenotype. In the present paper I go back to their role in the creation of modern genetics in the early twentieth century. The terms were introduced by the Danish botanist and geneticist Wilhelm Johannsen in his big textbook of 1909. Historical accounts usually concentrate on this book and his 1911 paper "The Genotype Conception of Heredity." His bean selection experiment of 1900-1903 is generally assumed to be the source of his genotype theory. The present paper examines the scientific context and meaning of this experiment, how it was received, and how the genotype theory became securely established by the early 1910s. I argue in conclusion that the genotype/phenotype distinction, which provides the empirical basis for Johannsen's gene, was scientifically well founded when introduced and still is. Keith Baverstock's criticism does not consider the force of the bean selection experiment at the time and as a paradigm for following investigations of heredity.

Revisiting the Pouchet-Pasteur controversy over spontaneous generation: understanding experimental method.

Louis Pasteur's defeat of belief in spontaneous generation has been a classical rationalist example of how the experimental approach of modern science can reveal superstition. Farley and Geison (Bull Hist Med 48:161-198, 1974) told a counter-story of how Pasteur's success was due to political and ideological support rather than superior experimental science. They claimed that Pasteur violated proper norms of scientific method, and that the French Academy of Science did not see this, or did not want to. Farley and Geison argued that Pouchet's experiments were as valid as those of Pasteur. In this paper I argue that the core of the scientific debate was not general theories for or against spontaneous generation but the outcome of specific experiments. It was on the conduct of these experiments that the Academy made judgements favorable to Pasteur. Claude Bernard was a colleague of Pasteur, supportive and sometimes critical. I argue that Bernard's fact-oriented methodology of "experimental medicine" is a better guide to explaining the controversy than the hypothetic-deductive view of scientific method typical of logical empiricism.

Johannsen's criticism of the chromosome theory.

The genotype theory of Wilhelm Johannsen (1857-1927) was an important contribution to the founding of classical genetics. This theory built on Johannsen's experimental demonstration that hereditary change is discontinuous, not continuous as had been widely assumed. Johannsen is also known for his criticism of traditional Darwinian evolution by natural selection, as well as his criticism of the classical Mendelian chromosome theory of heredity. He has often been seen as one of the anti-Darwinians that caused the "eclipse of Darwinism" in the early 20th century, before it was saved by the Modern Synthesis. This article focuses on Johannsen's criticism of the chromosome theory. He was indeed skeptical of the notion of the chromosomes as the sole carriers of heredity, but he praised the mapping of Mendelian genes on the chromosomes as a major step forward. Johannsen objected that these genes could not account for the whole of heredity, and that the stability of the genotype depended on much more than the stability of Mendelian genes. For Johannsen, the genotype, as a property of the whole organism, was the fundamental and empirically well-established entity.

The holist tradition in twentieth century genetics. Wilhelm Johannsen's genotype concept.

The terms 'genotype', 'phenotype' and 'gene' originally had a different meaning from that in the Modern Synthesis. These terms were coined in the first decade of the twentieth century by the Danish plant physiologist Wilhelm Johannsen. His bean selection experiment and his theoretical analysis of the difference between genotype and phenotype were important inputs to the formation of genetics as a well-defined special discipline. This paper shows how Johannsen's holistic genotype theory provided a platform for criticism of narrowly genocentric versions of the chromosome theory of heredity that came to dominate genetics in the middle decades of the twentieth century. Johannsen came to recognize the epoch-making importance of the work done by the Drosophila group, but he continued to insist on the incompleteness of the chromosome theory. Genes of the kind that they mapped on the chromosomes could only give a partial explanation of biological heredity and evolution.

Sources of Wilhelm Johannsen's genotype theory.

This paper describes the historical background and early formation of Wilhelm Johannsen's distinction between genotype and phenotype. It is argued that contrary to a widely accepted interpretation (For instance, W. Provine, 1971. The Origins of Theoretical Population Genetics. Chicago: The University of Chicago Press; Mayr, 1973; F. B. Churchill, 1974. Journal of the History of Biology 7: 5-30; E. Mayr, 1982. The Growth of Biological Thought, Cambridge: Harvard University Press; J. Sapp, 2003. Genesis. The Evolution of Biology. New York: Oxford University Press) his concepts referred primarily to properties of individual organisms and not to statistical averages. Johannsen's concept of genotype was derived from the idea of species in the tradition of biological systematics from Linnaeus to de Vries: An individual belonged to a group - species, subspecies, elementary species - by representing a certain underlying type (S. Müller-Wille and V. Orel, 2007. Annals of Science 64: 171-215). Johannsen sharpened this idea theoretically in the light of recent biological discoveries, not least those of cytology. He tested and confirmed it experimentally combining the methods of biometry, as developed by Francis Galton, with the individual selection method and pedigree analysis, as developed for instance by Louis Vilmorin. The term "genotype" was introduced in W. Johannsen's 1909 (Elemente der Exakten Erblichkeitslehre. Jena: Gustav Fischer) treatise, but the idea of a stable underlying biological "type" distinct from observable properties was the core idea of his classical bean selection experiment published 6 years earlier (W. Johannsen, 1903. Ueber Erblichkeit in Populationen und reinen Linien. Eine Beitrag zur Beleuchtung schwebender Selektionsfragen, Jena: Gustav Fischer, pp. 58-59). The individual ontological foundation of population analysis was a self-evident presupposition in Johannsen's studies of heredity in populations from their start in the early 1890s till his death in 1927. The claim that there was a "substantial but cautious modification of Johannsen's phenotype-genotype distinction" (Churchill, 1974, p. 24) from a statistical to an individual ontological perspective derives from a misreading of the 1903 and 1909 texts. The immediate purpose of this paper is to correct this reading of the 1903 monograph by showing how its problems and results grow out of Johannsen's earlier work in heredity and plant breeding. Johannsen presented his famous selection experiment as the culmination of a line of criticism of orthodox Darwinism by William Bateson, Hugo de Vries, and others (Johannsen, 1903). They had argued that evolution is based on stepwise rather than continuous change in heredity. Johannsen's paradigmatic experiment showed how stepwise variation in heredity could be operationally distinguished from the observable, continuous morphological variation. To test Galton's law of partial regression, Johannsen deliberately chose pure lines of self-fertilizing plants, a pure line being the descendants in successive generations of one single individual. Such a population could be assumed to be highly homogeneous with respect to hereditary type, and Johannsen found that selection produced no change in this type. Galton, he explained, had experimented with populations composed of a number of stable hereditary types. The partial regression which Galton found was simply an effect of selection between types, increasing the proportion of some types at the expense of others.

Wishful science: the persistence of T. D. Lysenko's agrobiology in the politics of science.

The suppression of genetics in Soviet Russia was the big scandal of twentieth-century science. It was also a test case for the role of scientists in a liberal democracy. The intellectual's perennial dilemma between scientific truthfulness and political loyalty was sharpened by acute ideological conflicts. The central topic of this essay is how the conflict was played out in Soviet agricultural and biological science in the 1930s and 1940s. The account is focused on the role of the then current Soviet science policy and its basic epistemic principles, the "unity of theory and practice" and the "practice criterion of truth".

The Lysenko effect: undermining the autonomy of science.

The "Lysenko affair", which lasted roughly from the mid-1930s to the mid-1960s, was the big scandal of 20th-century science: a classic example of how politics can corrupt and undermine its rational basis. Under Stalin's leadership the Soviet Government suppressed genuine genetics and other sound biology, with devastating consequences for agriculture and health. The worst example of this occurred in August 1948 when the Politburo outlawed the teaching of and research into classical Mendelian genetics. There is broad agreement that this case offers a stark warning against politicians interfering with science. But what, precisely, is this interference that we are being warned about? Whereas the fate of genetics in Soviet Russia was a clear-cut example of direct suppression, there were also other less obvious ways in which politics subverted the scientific process. This indirect interference with science is a persistent feature of modern politics that we need to be on the lookout for.

Plant breeding on the front: imperialism, war, and exploitation.

This paper examines the development of plant-breeding science in the context of the booming genetic research and autarky policy of the 1930s as well as during World War II in National Socialist-occupied Europe. Soviet scientists, especially Nikolai Vavilov and his VIR institute, had a leading position in the international plant-breeding science of the 1920s. During World War II, German scientists, namely experts from the Kaiser Wilhelm Institute for Plant Breeding, usurped Soviet institutes and valuable seed collections. In contrast, plant-breeding research in occupied Scandinavia continued with relatively little disturbance. The paper compares behavior of German, Soviet, and Norwegian plant-breeding scientists under the Nazi regime.