J. B. S. Haldane, Ernst Mayr and the Beanbag Genetics Dispute

Abstract

Starting from the early decades of the twentieth century, evolutionary biology began to acquire mathematical overtones. This took place via the development of a set of models in which the Darwinian picture of evolution was shown to be consistent with the laws of heredity discovered by Mendel. The models, which came to be elaborated over the years, define a field of study known as population genetics. Population genetics is generally looked upon as an essential component of modern evolutionary theory. This article deals with a famous dispute between J. B. S. Haldane, one of the founders of population genetics, and Ernst Mayr, a major contributor to the way we understand evolution. The philosophical undercurrents of the dispute remain relevant today. Mayr and Haldane agreed that genetics provided a broad explanatory framework for explaining how evolution took place but differed over the relevance of the mathematical models that sought to underpin that framework. The dispute began with a fundamental issue raised by Mayr in 1959: in terms of understanding evolution, did population genetics contribute anything beyond the obvious? Haldane's response came just before his death in 1964. It contained a spirited defense, not just of population genetics, but also of the motivations that lie behind mathematical modelling in biology. While the difference of opinion persisted and was not glossed over, the two continued to maintain cordial personal relations.

“Genetic Load”

“…Although population genetics may benefit from the simplifying value of the biostatisticians' assumptions (Crow 2001), mathematical models also act as idealized constructions that embark scientists into "fictional states of affairs" (Godfrey-Smith 2009;Rao & Nanjundiah 2011). Idealization is a cognitive operation that allows for treating things as if they possessed features they do not have but would be concrete if real.…”

“…-Scientific crisis: Controversies surrounding the genetic load led to the birth of the Neutral Theory and contributed to the end of the synthesis (Dreuil 1996;Rao & Nanjundiah 2011). When, in 1966, Richard C. Lewontin and Jack Hubby discovered the magnitude of polymorphism in natural populations at the molecular level, they questioned the sheer phenomenon of genetic load.…”

Jogos tipo “bean bag” em aulas de evolução

“…Na Bean Bag Genetics, segundo ele, cada locus era estudado separadamente com a finalidade de simplificar as análises o que, para Mayr, era inaceitável (DRONAMRAJU, 2011). Embora reconhecendo a grande contribuição da Bean Bag Genetics, Mayr afirmava que ela não era capaz de dar respostas adequadas para questões evolutivas centrais como a especiação e a adaptação (RAO, 2011).…”

What is life? And what might be said of the role of behaviour in its evolution?

“…This tight inter‐relationship lay at the heart of Ernst Mayr's dissatisfaction with ‘beanbag’ genetics (Rao & Nanjundiah, ). Haukioja () suggested that one cannot understand evolution without understanding the different and necessary relationship between existence (the processes of living, including reproduction) and change in lineages through time (the processes of evolution).…”