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.

[Cancer between infection and heredity: genes, viruses and mice at National Cancer Institute (1937-1977)]. / Le cancer entre infection et hérédité: gènes, virus et souris au National Cancer Institute (1937-1977).

After World War II, in the United States,viral explanation of cancer replaced a vision of the disease emphasizing genetic factors. From the mid 1950s onwards, experimental oncologists favored the notion that cancer was initiated by infectious agents passed from one generation to the next. In order to analyze this displacement, the present paper focuses on the part played by new experimental systems, i.e. mice showing tumors induced by viruses. Since animal models are agencies which "represent" human diseases, and mediate between different social worlds, their uses often result in opposing views. Mouse models thus provided tractable resources which favored the alternation between heredity and infection. The paper describes the emergence, in the late 1930s, at the Jackson Memorial Laboratory, of an agent enhancing the formation of mammary tumors in mice. This laboratory was then involved in the production of marketable inbred mice as well as in research concerned with genetic factors that may cause cancer. After World War II, loose theories and conflicting results helped turn the agent into a virus. At the National Cancer Institute, the virus was associated with a whole range of particles causing leukemia in mice. Owing to the Virus Cancer Program, the value of mouse tumor viruses increased in the late 1960s. This research effort then aimed at finding human tumor viruses, and at crafting cancer vaccines. It was modeled after the experience of the NCI chemotherapy program stemming from war research. In addition to the fact that biomedical research became a state enterprise, the study emphasizes three parameters. First, loose practices--both theoretical and experimental--helped manage the variability of animal models. Secondly, the standardization and mass production of animals and reagents encouraged the stabilization of research programs. Thirdly, private biotechnology companies working under NCI contracts implemented preclinical work, and mediated between virology laboratories and clinical settings.

Prenylation and methylation reactions in phylloquinone (vitamin K1) synthesis in Capsicum annuum plastids.

The biosynthesis of phylloquinone (vitamin K1) was examined using Capsicum fruit chloroplasts and chromoplasts (apparently phylloquinone free). In both cases, the synthesis of phylloquinone from α-naphthoquinone, dihydro-α-naphthoquinone, 1,4-dihydroxy-2-naphthoic acid (as precursors of the ring moiety) and (S)-adenosyl-L-methionine was achieved. In the presence of phytylpyrophosphate, the biosynthesis of phylloquinone in both organelles is particularly enhanced when 1,4-dihydroxy-2-naphthoic acid is used.