Waddington’s Unfinished Critique of Neo-Darwinian Genetics: Then and Now

Abstract

C.H. Waddington is today remembered chiefly as a Drosophila developmental geneticist who developed the concepts of “canalization” and “the epigenetic landscape.” In his lifetime, however, he was widely perceived primarily as a critic of Neo-Darwinian evolutionary theory. His criticisms of Neo-Darwinian evolutionary theory were focused on what he saw as unrealistic, “atomistic” models of both gene selection and trait evolution. In particular, he felt that the Neo-Darwinians badly neglected the phenomenon of extensive gene interactions and that the “randomness” of mutational effects, posited in the theory, was a false postulate. This last criticism dealt with the phenomenon known today as “developmental constraints.” Although population genetics itself has evolved considerably from its form at mid-20th century, much of Waddington’s critique, it is argued here, retains cogency. Yet, he did not attempt to develop a full-fledged alternative theory himself. Perhaps most surprisingly, in retrospect, is that he did not try to marry his work on gene interactions in development with his evolutionary interests, to create a theory of “genetic networks” and their evolution. Whether evolutionary genetics today will incorporate “network thinking” as a central element or whether there will be a general retreat to the more atomistic approach offered by genomics, remains an open question.