The technique of nuclear transplantation – popularly known as cloning – has been integrated into several different histories of twentieth century biology. Historians and science scholars have situated nuclear transplantation within narratives of scientific practice, biotechnology, bioethics, biomedicine, and changing views of life. However, nuclear transplantation has never been the focus of analysis. In this article, I examine the development of nuclear transplantation techniques, focusing on the people, motivations, and institutions associated with the first successful nuclear transfer in metazoans in (...) 1952. The conflict between embryologists and geneticists over the mechanisms of differentiation motivated Robert Briggs to pursue nuclear transplantation experiments as a way to resolve the debate. Briggs worked at the Lankenau Hospital Research Institute, a research facility devoted to the study of cancer. The goal of understanding cancer would play a role in the development of the technique, and the story of nuclear transplantation sheds light on the role that biomedical contexts play in biological research in the second half of the twentieth century. (shrink)

Linkage (or genetic) maps are graphs, which are intended to represent the linear ordering of genes on the chromosomes. They are constructed on the basis of statistical data concerning the transmission of genes. The invention of this technique in 1913 was driven by Morgan's group's adoption of a set of hypotheses concerning the physical mechanism of heredity. These hypotheses were themselves grounded in Morgan's defense of the chromosome theory of heredity, according to which chromosomes are the physical basis of genes. (...) In this paper, I analyze the 1919 debate between William Castle and Morgan's group, about the construction of genetic maps. The official issue of the debate concerns the arrangement of genes on chromosomes. However, the disputants tend to carry out the discussions about how one should model the data in order to draw predictions concerning the transmission of genes; the debate does not bear on the data themselves, nor does it focus on the hypotheses explaining these data. The main criteria that are appealed to by the protagonists are simplicity and predictive efficacy. However, I show that both parties' assessments of the simplicity and predictive efficacy of different ways of modeling the data themselves depend on background theoretical positions. I aim at clarifying how preference for a given model and theoretical commitments articulate. (shrink)

The traditional practice of establishing morphological types and investigating morphological organization has found new support from evolutionary developmental biology (evo-devo), especially with respect to the notion of body plans. Despite recurring claims that typology is at odds with evolutionary thinking, evo-devo offers mechanistic explanations of the evolutionary origin, transformation, and evolvability of morphological organization. In parallel, philosophers have developed non-essentialist conceptions of natural kinds that permit kinds to exhibit variation and undergo change. This not only facilitates a construal of species (...) and higher taxa as natural kinds, but also broadens our perspective on the diversity of kinds found in biology. There are many different natural kinds relevant to the investigative and explanatory aims of evo-devo, including homologues and developmental modules. (shrink)

Richard Goldschmidt famously rejected the notion of atomic and corpuscular genes, arranged on the chromosome like beads-on-a-string. I provide an exegesis of Goldschmidt’s intuition by analyzing his repeated and extensive use of metaphorical language and analogies in his attempts to convey his notion of the nature of the genetic material and specifically the significance of chromosomal pattern. The paper concentrates on Goldschmidt’s use of metaphors in publications spanning 1940-1955. -/- .

Throughout the 1930s two of Germany’s most senior geneticists were caught up in controversy as they tried to enter the distinctly American culture of Drosophila genetics. When Richard Goldschmidt and Victor Jollos were forced by the Nazis to leave Germany in 1936 and 1933, respectively, this type of conflict intensified. The experiences of Goldschmidt and Jollos as émigré scientists are interpreted in terms of a conflict of scientific styles of thought. Their Americanization, I claim, involved the modification of their scientific (...) styles and consequently the ways in which they conceived of and presented their scientific work. (shrink)

Bateson's belated acceptance of the chromosome theory came in two main stages, and was permanent, although he retained to the end reservations about some implications and extensions of the theory. Coleman's attempt to explain Bateson's resistance in terms of his conservative mode of thought is critically examined, and rejected: the attributes Coleman assigns to Bateson are all either inappropriate, or irrelevant to chromosome theory, or both. Instead, the diverse factors which contributed to Bateson's resistance are enumerated and discussed. These include (...) deficiencies in the evidence then available to support the theory; embryological difficulties; Bateson's aversion to microscopy combined with the lack of a close colleague skilled in cytology; his iconoclastic temperament, and the fact that he found T. H. Morgan, the leader of the Drosophila school, an uncongenial personality. Taken together, these factors suffice to account for his resistance. Bateson's position is contrasted with that of the other most eminent opponent, W. Johannsen, whose organismic outlook was the main obstacle to acceptance. (shrink)

At the turn of the twentieth century, biologists such as Oscar Riddle, Thomas Hunt Morgan, Frank Lillie, and Richard Goldschmidt all puzzled over the question of sexual difference, the distinction between male and female. They all offered competing explanations for the biological cause of this difference, and engaged in a fierce debate over the primacy of their respective theories. Riddle propounded a metabolic theory of sex dating from the late-nineteenth century suggesting that metabolism lay at the heart of sexual difference. (...) Thomas Hunt Morgan insisted on the priority of chromosomes, Frank Lillie emphasized the importance of hormones, while Richard Goldschmidt supported a mixed model involving both chromosomes and hormones. In this paper, I will illustrate how the older metabolic theory of sex was displaced when those who argued for the relatively newer theories of chromosomes and hormones gradually formed an alliance that accommodated each other and excluded the metabolic theory of sex. By doing so, proponents of chromosomes and hormones established their authority over the question of sexual difference as they laid the foundations for the new disciplines of genetics and endocrinology. Their debate raised urgent questions about what constituted sexual difference, and how scientists envisioned the plasticity and controllability of this difference. These theories also had immediate political and cultural consequences at the turn of the twentieth century, especially for the eugenic and feminist movements, both of which were heavily invested in knowledge of sex and its determination, ascertainment, and command. (shrink)

Genetics was established on a strict particulate conception of heredity. Genetic linkage, the deviation from independent segregation of Mendelian factors, was conceived as a function of the material allocation of the factors to the chromosomes, rather than to the multiple effects (pleiotropy) of discrete factors. Although linkage maps were abstractions they provided strong support for the chromosomal theory of inheritance. Direct Cytogenetic evidence was scarce until X-ray induced major chromosomal rearrangements allowed direct correlation of genetic and cytological rearrangements. Only with (...) the discovery of the polytenic giant chromosomes in Drosophila larvae in the 1930s were the virtual maps backed up by physical maps of the genetic loci. Genetic linkage became a pivotal experimental tool for the examination of the integration of genetic functions in development and in evolution. Genetic mapping has remained a hallmark of genetic analysis. The location of genes in DNA is a modern extension of the notion of genetic linkage. (shrink)

ZusammenfassungDer Artikel führt den Begriff der epistemischen Konkurrenz ein. Im Gegensatz zu „wissenschaftliche Kontroverse“ beschreibt er eine Situation, in der sich zwei Forschungsfelder gegenseitig als mit demselben Bereich von Phänomen befasst wahrnehmen, wobei ihre methodischen Ansätze und theoretischen Erklärungen jedoch so unterschiedlich sind, dass ein offener Konflikt über die Wahrheit oder Falschheit bestimmter Aussagen oder die Genauigkeit in der Anwendung einer Methode nicht stattfindet. Nichtsdestotrotz streben beide Parteien danach, die maßgebliche Erklärung der entsprechenden Phänomene anzubieten. Indem die erweiterte Gemeinschaft der (...) Forschenden oder die Öffentlichkeit einen Ansatz als maßgeblich anerkennt, handeln sie als eine dritte, gewissermaßen neutrale Partei, die einen Preis vergibt, um den die anderen Parteien konkurrieren. Der Artikel beschreibt das Verhältnis von Genetik und Entwicklungsbiologie um 1900 als epistemische Konkurrenz. Diese Forschungsfelder geben unterschiedliche Erklärungen für die Phänomene der organischen Reproduktion. Die Erklärungen unterscheiden sich bezüglich der Formbegriffe und entsprechend hinsichtlich der Begriffe der Vererbung von Aspekten der Form eines Organismus. Zudem basieren die Erklärungen der beiden Felder auf unterschiedlichen Arten kausalen Schließens, die in unterschiedliche experimentelle Ansätze eingebettet sind. Diese Unterschiede können als Instanzen eines allgemeineren Unterschieds zwischen der Tradition der Naturgeschichte, die sich mit Unterschieden zwischen Organismen auseinandersetzt, und der Tradition der Anatomie, die sich mit den Teilen der Organismen beschäftigt, angesehen werden. Dieses Bild der Genetik und Entwicklungsbiologie als Zweige unterschiedlicher fest verankerter Traditionen widerspricht dem Narrativ der Trennung des Begriffs der Vererbung von dem der Entwicklung im Zuge einer Trennung der Disziplinen der Genetik und der Embryologie, das in der Historiographie der Biologie nach wie vor weit verbreitet ist. (shrink)

Much of the early history of developmental and physiological genetics in Germany remains to be written. Together with Carl Correns and Richard Goldschmidt, Alfred Kühn occupies a special place in this history. Trained as a zoologist in Freiburg im Breisgau, he set out to integrate physiology, development and genetics in a particular experimental system based on the flour moth Ephestia kühniella Zeller. This paper is meant to reconstruct the crucial steps in the experimental pathway that led Kühn and his collaborators (...) at the University of Göttingen, and later at the Kaiser Wilhelm Institutes of Biology and Biochemistry in Berlin, to formulate, in their specific way, what later became known as the "one gene-one enzyme hypothesis." Special attention will be given to the interaction of the different parts of Kühn's Ephestia-based project, which were rooted in different research traditions. The paper retraces how, roughly between 1925 and 1945, these elements came to form a mixed experimental setup composed of genetic, embryological, physiological and, finally, biochemical constituents. Accordingly, emphasis is laid on the development of the terminology in which the results were cast, and how it reflected the hybrid state of an experimental system successively acquiring new epistemic layers. (shrink)

ABSTRACT A rereading of the American scientific literature on sex determination from 1902 to 1926 leads to a different understanding of the construction of the Mendelian‐chromosome theory after 1910. There was significant intellectual continuity, which has not been properly appreciated, underlying this scientific “revolution.” After reexamining the relationship between the ideas of key scientists, in particular Edmund B. Wilson and Thomas Hunt Morgan, I argue that, contrary to the historical literature, Wilson and Morgan did not adopt opposing views on Mendelism (...) and sex determination. Rather, each preferred a non‐Mendelian explanation of the determination of sex. Around 1910, both integrated the Mendelian and non‐Mendelian theories to create a synthetic theory. One problem was the need to avoid an overly deterministic view of sex while also accepting the validity of Mendelism. Morgan’s discovery of mutations on the X chromosome takes on different significance when set in the context of the debate about sex determination, and Calvin Bridges’s work on sex determination is better seen as a development of Morgan’s ideas, rather than a departure from them. Conclusions point to the role of synthesis within fields as a way to advance scientific theories and reflect on the relationship between synthesis and explanatory “pluralism” in biology. (shrink)

In this paper, I wish to challenge theory-biased approaches to scientific knowledge, by arguing for a study of theorizing, as a cognitive activity, rather than of theories, as abstract structures independent from the agents’ understanding of them. Such a study implies taking into account scientists’ reasoning processes, and their representational practices. Here, I analyze the representational practices of geneticists in the 1910s, as a means of shedding light on the content of classical genetics. Most philosophical accounts of classical genetics fail (...) to distinguish between the purely genetic, or Mendelian level, and the cytological one. I distinguish between them by characterizing them in terms of their respective associated representational practices. I then present how the two levels were articulated within Morgan’s theory of crossing-over, and I describe the representational technique of linkage mapping, which embodies the “merging” of the Mendelian and cytological levels. I propose an analysis of the mapping scheme, as a means of enlightening the conceptual articulation of Mendelian and cytological hypotheses within classical genetics. Finally, I present the respective views of three opponents to Morgan in the 1910s, who had a different understanding of the articulation of cytology and Mendelism, and entertained different views concerning the role and proper interpretation of maps. I propose to consider these diverging perspectives as instantiating what I call different “versions” of classical genetics. (shrink)

Der Artikel führt den Begriff der epistemischen Konkurrenz ein. Im Gegensatz zu „wissenschaftliche Kontroverse“ beschreibt er eine Situation, in der sich zwei Forschungsfelder gegenseitig als mit demselben Bereich von Phänomen befasst wahrnehmen, wobei ihre methodischen Ansätze und theoretischen Erklärungen jedoch so unterschiedlich sind, dass ein offener Konflikt über die Wahrheit oder Falschheit bestimmter Aussagen oder die Genauigkeit in der Anwendung einer Methode nicht stattfindet. Nichtsdestotrotz streben beide Parteien danach, die maßgebliche Erklärung der entsprechenden Phänomene anzubieten. Indem die erweiterte Gemeinschaft der (...) Forschenden oder die Öffentlichkeit einen Ansatz als maßgeblich anerkennt, handeln sie als eine dritte, gewissermaßen neutrale Partei, die einen Preis vergibt, um den die anderen Parteien konkurrieren. Der Artikel beschreibt das Verhältnis von Genetik und Entwicklungsbiologie um 1900 als epistemische Konkurrenz. Diese Forschungsfelder geben unterschiedliche Erklärungen für die Phänomene der organischen Reproduktion. Die Erklärungen unterscheiden sich bezüglich der Formbegriffe und entsprechend hinsichtlich der Begriffe der Vererbung von Aspekten der Form eines Organismus. Zudem basieren die Erklärungen der beiden Felder auf unterschiedlichen Arten kausalen Schließens, die in unterschiedliche experimentelle Ansätze eingebettet sind. Diese Unterschiede können als Instanzen eines allgemeineren Unterschieds zwischen der Tradition der Naturgeschichte, die sich mit Unterschieden zwischen Organismen auseinandersetzt, und der Tradition der Anatomie, die sich mit den Teilen der Organismen beschäftigt, angesehen werden. Dieses Bild der Genetik und Entwicklungsbiologie als Zweige unterschiedlicher fest verankerter Traditionen widerspricht dem Narrativ der Trennung des Begriffs der Vererbung von dem der Entwicklung im Zuge einer Trennung der Disziplinen der Genetik und der Embryologie, das in der Historiographie der Biologie nach wie vor weit verbreitet ist. (shrink)