“…this Brazilian venture…” A brief biography of Theodosius Dobzhansky before he arrived in Brazil

This paper describes life and career of Theodosius Dobzhansky (1900-1975) until he arrived in Brazil in 1943. During his years in Russia, Dobzhansky began his entomology studies and undertook research expeditions to Central Asia to study livestock, which focused on speciation biology. Once he arrived in the United States Dobzhansky began working with Drosophila melanogaster with Thomas Hunt Morgan (1866-1945) at Columbia University. Once Morgan relocated to the California Institute of Technology (Caltech), Dobzhansky started collaborating with his colleague, Alfred Henry Sturtevant (1891-1970), on studies of a wild cousin of Drosophila melanogaster, Drosophila pseudoobscura. Dobzhansky and Sturtevant’s friendship and collaboration suffered due to several factors, including most importantly, their differing approaches to Drosophila pseudoobscura as influenced by their different conceptions of the purpose of their work. While Sturtevant studied the flies using the same techniques as his studies of the domestic Drosophila melanogaster, Dobzhansky studied Drosophila pseudoobscura in the field considering his broader dictum that “Nothing in biology makes sense except in the light of evolution.”

Dobzhansky and Dreyfus’s Group: The Introduction of Natural Population Genetics Studies in Brazil (1943–1960)

An important center in which genetic research started and was carried out in Brazil during the 20th century was situated at the Faculty of Philosophy, Sciences and Linguistics of the University of São Paulo, led by André Dreyfus (1897–1952). Beginning in 1943, the Ukrainian geneticist Theodosius Dobzhansky (1900–1975) visited Dreyfus’s group four times. This paper evaluates the impact of Dobzhansky’s visits on the studies of genetics and evolution developed by the members of Dreyfus’s group during the 1940s and the 1950s. The study leads to the conclusion that Dobzhansky’s visits had an impact, not only in quantitative terms (the number of individual and joint publications), but also in qualitative terms. However, we also detect a decrease in the number of individual and joint publications related to the subject of the project during certain periods. The adoption of new experimental organisms by some members of the group; the involvement with subjects not related to the initial project, such as botany; Dobzhansky’s and his wife’s health problems during the third visit; and scientific disagreements between Dobzhansky and Brazilian researchers may have contributed to the decrease in publications.

Modern Evolutionary Biology and Brazilian Population Genetics: Theodosius Dobzhansky at the University of São Paulo

On the one hand, much has been written on Theodosius Dobzhansky’s central role in the development of the field of population genetics and modern evolutionary theory, as well as on his sociopolitical worldview in the middle of the Twentieth Century. On the other hand, much has also been written on Dobzhansky’s role in the institutionalization of genetics in Brazil, where he spent a considerable amount of time. Unfortunately, these literatures developed without any points of intersection or cross-reference. This article places Dobzhansky’s work in Brazil in the broader contexts of the science and politics of its historical period.

“A most bountiful source of inspiration:” Dobzhansky’s evolution of tropical populations, and the science and politics of genetic variation

Theodosius Dobzhansky has been studied for how he integrated field naturalism and laboratory experimentation in ways that helped produce the Modern Synthesis, as well as how he leveraged biological expertise to support liberal and cosmopolitan values amidst Second World War and the Cold War. Moreover, Dobzhansky has been central in analyses of the institutionalization of genetics in Brazil, where he spent several years. This article situates Dobzhansky’s Brazilian research within the science of variation and the politics of diversity. I conclude by raising questions about how the ways in which science figured in politics depended on ideas about the role of scientists in society whichwere advanced in parallel, suggesting research on the “co-production” of natural and social orders.

“Genetic Load”: How the Architects of the Modern Synthesis Became Trapped in a Scientific Ideology

The term “genetic load” first emerged in a paper written in 1950 by the geneticist H. Muller. It is a mathematical model based on biological, social, political and ethical arguments describing the dramatic accumulation of disadvantageous mutations in human populations that will occur in modern societies if eugenic measures are not taken. The model describes how the combined actions of medical and social progress will supposedly impede natural selection and make genes of inferior quality likely to spread across populations – a process which in fine loads their progress. Genetic load is based on optimal fitness and emerges from a “typological view” of evolution. This model of evolution had previously, however, been invalidated by Robert Wright and Theodosius Dobzhansky who, as early as 1946, showed that polymorphism was the rule in natural populations. The blooming and persistence of the concept of genetic load, after its theoretical basis had already expired, are a historical puzzle. This persistence reveals the intricacy of science and policy-making in eugenic matters. The Canguilhemian concept of ‘scientific ideology’ (1988) is used along with the concept of ‘immutable mobile’ (Latour 1986) and compared with the concept of ‘co-production’ (Jasanoff 1998), to provide complementary perspectives on this complex phenomenon.

The Question of Diversity

Tracing the fieldwork and ideas of Robert H. MacArthur, Howard T. Odum, and Theodosius Dobzhansky, chapter 4 examines the post­World War II rise of efforts to capture the complexity of tropical nature using a simplified quantitative measure: species diversity. The new approaches were abstract but were shaped by U.S. biologists’ experiences in an increasingly wide array of sites within and beyond the circum­Caribbean—facilitated by the U.S. government’s interest in tropical warfare, demand for tropical products, and the growth in air travel. The rise of mathematical and systems approaches in ecology, along with the population perspective of the modern evolutionary synthesis, recast the old question of the biological difference of the tropics. The need for tropical data to solve biology’s core theoretical problems was now unquestionable.