Opposition to the Mendelian-chromosome theory: the physiological and developmental genetics of Richard Goldschmidt

Experimenting with sex: four approaches to the genetics of sex reversal before 1950

In the early twentieth century, Tatsuo Aida in Japan, Øjvind Winge in Denmark, Richard Goldschmidt in Germany, and Calvin Bridges in the United States all developed different experimental systems to study the genetics of sex reversal. These locally specific experimental systems grounded these experimenters' understanding of sex reversal as well as their interpretation of claims regarding experimental results and theories. The comparison of four researchers and their experimental systems reveals how those different systems mediated their understanding of genetic phenomena, and influenced their interpretations of sex reversal.

The riddle of sex: biological theories of sexual difference in the early twentieth-century

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.

Maintaining continuity through a scientific revolution: a rereading of E. B. Wilson and T. H. Morgan on sex determination and Mendelism

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.

Richard Goldschmidt: hopeful monsters and other 'heresies'

Richard Goldschmidt is remembered today as one of the most controversial biologists of the twentieth century. Although his work on sex determination and physiological genetics earned him accolades from his peers, his rejection of the classical gene and his unpopular theories about evolution significantly damaged his scientific reputation. This article reviews Goldschmidt's life and work, with an emphasis on his controversial views.

Gene function

The problem of gene function--of the relationships between hereditary material and the characteristics of organisms--preceded the rediscovery of Mendel's laws and accompanied the development of genetics in the XXth century. Molecular biologists replaced the simple gene-character relationship by two relationships: the first, between genes and proteins, was well defined, whereas the second between proteins and the complex structural and functional characteristics of organisms remained unknown. I will describe in this article the experimental approaches which helped to characterize during the last twenty years the relationships between proteins and characters. Four principles of macromolecular organization emerged from these studies: conservation of the elementary components during evolution, existence of pathways and networks, pleiotropy and redundancy. These principles are the explanation of the surprising experimental observations that have been made in recent years. The existence of these principles makes problematic any prediction on the consequences of gene modification. It both sounds the death-knell of the simplistic reductionist approach of many biologists, whereby genes were considered as responsible for specific functions, and definitely prevents the distribution of genes in separate, well defined categories.

The problem of the gene

During the early 20th century the diverse practices of genetics were unified by the concept of the gene. This classical gene was simultaneously a unit of structure, function, mutation, and recombination. Starting in the 1940s, however, the classical gene began to fragment. Today when we speak of a gene for some malady, a regulatory gene, a structural gene, or a gene frequency, it is entirely possible that we are deploying different gene concepts even though we are using the same term. The problem of the gene addresses the fragmentation of the classical gene concept by asking to what extent a comprehensive and unifying gene concept is possible or desirable. Fully comprehensive gene concepts seem untenable today, but, within different disciplinary domains, unifying, but non-comprehensive, gene concepts can be epistemically worthwhile. The problem of the gene persists, however, not because of its epistemic value, but because of its political value. Using both the arguments for newly proposed gene concepts and the historical dispute over the classical gene, I argue that the desirability of gene concepts rests in part on the political ramifications of their deployment and contestation.