CHANGES IN THE GENETIC MENTALITY BRUCE WALLACE* Pique at indignities I recently suffered at the hands of an anonymous reviewer caused me to lament "Oh, how geneticists have changed": geneticists familiar with numbers and the meaning of numbers are disappearing . Or, so it seemed. After sober thought, however, I am now prepared to admit that the change in genetic mentality has been, contrary to my initial impression, an example of micro-, not of macro- or even of meso-, evolution. A change has occurred in the frequency of a certain type of biologist who for the moment will remain unidentified except to claim that he (and I use the bisexual "he") occurred originally almost exclusively among geneticists. This type of geneticist has probably not decreased in absolute numbers; he has decreased in frequency only because the ranks ofgeneticists have been swelled in recent years by workers from other branches ofbiology, workers who are now assigned, or claim for themselves, the title "geneticist." The success of modern genetics can be measured by the number of biological disciplines that it has invaded, not in a trivial sense but, rather, as the hypothesis-generating member of the union: if one of these invaded disciplines is to advance, it must now do so by incorporating modern genetics into its repertoire of concepts and hypotheses. Thus, from the former pool of physiologists and biochemists— scientists who once scarcely conversed with geneticists—have come modern molecular geneticists. From a second pool, the embryologists, have come today's developmental geneticists. And, from the ecologists ofyesterday have come the population biologist and sociobiologists who spend This paper was prepared while the author was a Fulbright lecturer at Alexandria University , Alexandria, Egypt, and while his research was supported by grant no. GM29810 from the National Institutes of Health, U.S. Public Health Service. It was presented as an invitational lecture at the 1983 annual meeting of the Genetics Society of Australia, May 20, 1983, University of New England, Armidale, New South Wales, Australia. ?Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg , Virginia 24061.© 1984 by The University of Chicago. AU rights reserved. 003 1-5982/84/2704-0405$01 .00 598 I Bruce Wallace · The Genetic Mentality considerable time predicting the genetic changes that might occur in populations under one or another of a variety of postulated conditions. Examples illustrating the point made here—namely, that the influx of other workers into genetics (and I could have included clinical physicians , many of whom are now referred to as medical geneticists) has caused one of the original, and formerly common, types of geneticists to become extremely rare—will be given as we go along. Here, let me merely point out that before Milislav Demerec became director of both the Department of Genetics, Carnegie Institution of Washington, and the Biological Laboratories during the early 1940s, the staffs of these two physically adjacent laboratories did not collaborate. The one was staffed by geneticists, the other by physiologists. I might also cite a second example, one to which I can personally attest. While being interviewed during the 1950s concerning a possible appointment to the university 's staff, I spent about an hour with Harvard's insect physiologist. When I suggested that he might profit fromjoining forces with a geneticist , the response was utter silence—the silence of one dumbfounded and, hence, momentarily unable to regain the thread of rational thought. That hormones should have any connection with genetics appeared as alien to his vision of the world as the notion that gene frequency analyses should be ofuse to an aeronautical engineer troubled by a vibrating airplane wing would have been to mine. A look at the origins of the science itself may prove useful. Between 1865, when Mendel published his paper on the study ofhybridization in peas, and 1900 when this work was rediscovered, Francis Galton developed his law ofancestral inheritance. Both Mendel and Galton sought to characterize an individual with respect to his heredity. Galton chose to study what flowed in from the past—from two parents, from four grandparents, from eight great-grandparents, and so on back through the family tree. Mayr [1] has commented on Galton's procedure by...