ALLOZYMES IN EVOLUTIONARY GENETICS - BEYOND THE TWIN PITFALLS OF NEUTRALISM AND SELECTIONISM

Population genetics arose as the algebraic study of genetic transmissi on in Mendelian populations, showing the genetic feasibility of Darwin ian evolution by natural selection. At the same time, it established a tradition of bypassing study of the biological mechanisms by which ev olution proceeds. This view of evolutionary dynamics as a primarily al gebraic, statistical matter led directly to the ''neutralist-selection ist'' controversy over the meaning of extensive allozyme variation in the wild. Much argument failed to resolve this controversy, demonstrat ing that population genetics by itself is necessary but insufficient f or full understanding of evolution, due to inherent limitations in the scope of its analysis. A broader concept of evolutionary genetics is proposed, using allozymes and/or other natural genetic variants as bio logically specific probes of putatively adaptive, constrained, or neut ral phenotypic states, and analyzing the translation of resulting geno typic differences in organismal performance into fitness consequences. This approach includes informed use of population-genetic concepts, b ut does not ask them to do more than they can do. Diverse examples are cited in support of the feasibility and productivity of this approach . Evolutionary biologists are challenged to bring mechanistic biology into Darwinian context, to move beyond the remains of the ''neutralist -selectionist'' controversy and of purely formal approaches to evoluti on, to seek biologically based generalities about the evolutionary pro cess.