This paper challenges the common assumption that some phenotypic traits are quantitative while others are qualitative. The distinction between these two kinds of traits is widely influential in biological and biomedical research as well as in scientific education and communication. This is probably due to both historical and epistemological reasons. However, the quantitative/qualitative distinction involves a variety of simplifications on the genetic causes of phenotypic variability and on the development of complex traits. Here, I examine three cases from the life (...) sciences that show inconsistencies in the distinction: Mendelian traits, Mendelian diseases, and polygenic mental disorders. I show that these traits can be framed both quantitatively and qualitatively depending, for instance, on the methods through which they are investigated and on specific epistemic purposes. This suggests that the received view of quantitative and qualitative traits has a limited heuristic power—limited to some local contexts or to the specific methodologies adopted. Throughout the paper, I provide directions for framing phenotypes beyond the quantitative/qualitative distinction. I conclude by pointing at the necessity of developing a principled characterisation of what phenotypic traits, in general, are. (shrink)

In 1933 Margaret Lasker, a biochemist who worked at the labs of Montefiore Hospital in New York, developed an accurate method for the differentiation between pentosuria and diabetes. Research into pentosuria, and mostly its genetic aspects, became Lasker’s lifelong passion. Since research was not part of her job description, she conducted the chief part of her study in her home kitchen. Lasker’s extensive and personal correspondence with her patients and their families may be the secret key for her success in (...) maintaining a prolonged research career against all odds. Laker’s last article was published in 1955 in Human Biology, presenting data on 72 cases of pentosuria, which occurs almost exclusively in Ashkenazi Jews. More than half a century later, and long after Lasker was gone, her well kept data and family records allowed the discovery of two mutations in the DCXR gene, by Mary-Claire King and her team. (shrink)

The origin and the development of scientific disciplines has been a topic of reflection for several decades. The few extensive case studies support the thesis that scientific disciplines are not monolithic structures but can be characterized by distinct social, organizational and scientific–technical practices. Nonetheless, most disciplinary histories of genetics confine themselves largely to an uncontested account of the content of the discipline or occasionally institutional factors. Little attention is paid to the large number of researchers who, by their joint efforts, (...) ultimately shaped the discipline. We contribute to this aspect of disciplinary historiography by discussing the role of women researchers at the Institute for Heredity Research, founded in 1914 in Berlin under the directorship of Erwin Baur, and the sister of the John Innes Institute at Cambridge. This paper investigates how and why Baur built a highly successful research programme that relied on the efforts of his female staff, whose careers, notably Elisabeth Schiemann's, are also assessedin toto. These women undertook the necessary ‘technoscience’ and in some cases innovative work and helped increase the prestige of the institute and its director. Together they played a pivotal role in the establishment of genetics in Germany. Without them the discipline would have developed much more slowly and along a divergent path. (shrink)

The beginning of the twentieth century saw the emergence of the discipline of genetics. It is striking how many female scientists were contributing to this new field at the time. At least three female pioneers succeeded in becoming professors: Kristine Bonnevie (Norway), Elisabeth Schiemann (Germany) and the Tine Tammes (The Netherlands). The question is which factors contributed to the success of these women's careers? At the time women were gaining access to university education it had become quite the norm for (...) universities to be sites for teaching and research. They were still expanding: new laboratories were being built and new disciplines were being established. All three women benefited from the fact that genetics was considered a new field promising in terms of its utility to society; in the case of Tammes and Schiemann in agriculture and in the case of Bonnevie in eugenics. On the other hand, the field of genetics also benefited from the fact that these first female researchers were eager for the chance to work in science and wanted to make active contributions. They all worked and studied in environments which, although different from one another, were positive towards them, at least at the start. Having a patron was generally a prerequisite. Tammes profited from her teacher's contacts and status. Bonnevie made herself indispensable through her success as a teacher and eventually made her position so strong that she was no longer dependent on a single patron. The case of Schiemann adds something new; it shows the vulnerability of such dependency. Initially, Schiemann's teacher had to rely on the first generation of university women simply because he was unable to attract ambitious young men to his institute. In those early, uncertain years of the new discipline, male scientists tended to choose other, better established, and more prestigious disciplines. However, when genetics itself had become an established field, it also became more attractive to men. Our case studies also demonstrate that a new field at first relatively open to women closes its doors to them once it becomes established. (shrink)

In addition to his experiments on selection in pure lines, Wilhelm Johannsen performed less well-known hybridisation experiments with beans. This article describes these experiments and discusses Johannsen’s motivations and interpretations, in the context of developments in early genetics. I will show that Johannsen first presented the hybridisation experiments as an additional control for his selection experiments. The latter were dedicated to investigating heredity with respect to debates concerning the significance of natural selection of continuous variation for evolution. In the course (...) of the establishment of a Mendelian research program after 1900, the study of heredity gained increasing independence from questions of evolution, and focused more on the modes and mechanisms of heredity. Further to their role as control experiments, Johannsen also saw his hybridisation experiments as contributing to the Mendelian program, by extending the scope of the principles of Mendelian inheritance to quantitative characters. Towards the end of the first decade of genetics, Johannsen revisited his experiments to illustrate the many–many relationship between genes and characters, at a time when that relationship appeared increasingly complex, and the unit-character concept, accordingly, became inadequate. For the philosophy of science, the example shows that experiments can have multiple roles in a research programme, and can be interpreted in the light of questions other than those that motivated the experiments in the first place. (shrink)