The comparative and the exemplary: revisiting the early history of molecular biology

INTRODUCTIONThe image and caricature of the biologist roaming the field with a collecting box or poring over pinned up insect and butterfly cases endured well into the twentieth century. In contrast the molecular vision of life, and even more so molecular biology, the quintessential science of the late twentieth century, has most often been connected with experimenting and intervening on a handful of model organisms and systems. Underpinning this widespread opposition is the idea that biology as practised by naturalists was "merely" descriptive, systematic, and comparative. Naturalists would rely on collecting and comparing specimens, providing names and descriptions, and thereby document biological diversity. This way of approaching the natural world was supposedly superseded by the experimental approach in the late nineteenth century, with molecular biologists taking up that banner in the twentieth. Using ever more powerful instruments, imported from the physical and chemical sciences, and focusing their attention on a few well-chosen model systems, they studied processes and their underlying mechanisms. This view of the history has been promoted by latter-day biologists and by historians alike.1 Historians of molecular biology have insisted, for example, on the crucial role of the Rockefeller Foundation, since the 1930s, in promoting molecular approaches in the life sciences by providing funding for the acquisition of costly new physical and chemical instruments.2 The molecular vision of life was predicated upon sophisticated means of intervention which produced representations enabling further manipulations of life.3 Equal attention has been dedicated to the strategic choice of a few simple model organisms on which much of the early work in molecular biology was developed. We can think here of Max Delbruck' s introduction of phage for the study of genetics, and the extensive use of bacteria and viruses in studying genetic mechanisms in molecular terms, but also of moulds (Neurospora crassa), flies (Drosophila melanogaster), and later, worms (Caenorhabditis elegans), mice (Mus Musculus), and weeds (Arabidopsis thaliana), which all gained the enviable status (at least from the researcher's perspective) of model organism for the production of knowledge in molecular biology.4One of the historiographie side-effects of writing disciplinary histories, such as those of molecular biology mentioned previously, has been a tendency to emphasize cognitive, methodological, and sociological unity within the disciplines and differences among disciplines. By contrast, John Pickstone's call to focus on "ways of knowing" (or "working knowledges"), rather than disciplines, can help us make visible the heterogeneity of cognitive and material practices within disciplines and the similarities among disciplines. Indeed, according to Pickstone, even though ways of knowing have their own historicity and have, for example, enjoyed their greatest successes at different times, they do not replace each other, like Kuhnian paradigms, but add new layers in the makeup of science, technology and medicine.5 Pickstone's historiographie approach, unlike that of many others proponents of 'styles', is not taxonomic, but analytic; it reveals the different components which make up scientific practices. This perspective proves fruitful for a closer examination of the working practices of modern biologists. As we show in this paper, molecular biology did not take shape exclusively as an experimental science focused on 'exemplary' model organism and systems. Rather, much work in molecular biology can be described more accurately as comparative and relied far more than previously recognized on collections. This is true not only for late twentieth-century genomic scientists, who have been derided as "molecular birdwatchers",6 but also of early day molecular biologists, those most vehement in condemning natural history.7 In their studies of the most challenging problems of the new science, namely the structure and function of proteins and nucleic acids and the deciphering of the genetic code, they relied heavily on collections and comparisons of molecular data, the distinctive approach of the comparative biological sciences, usually associated with nineteenth-century natural history, anatomy, and embryology. …