Population Structure and Processes in Evolution

Abstract

The strongest motivation for evolutionary biologists to study the effects of population structure is quite simply that most species of most organisms are subdivided, in the sense that not all pairs of individuals are equally likely to mate. Slight departures from panmixia will have no effect on evolution of the species if the subdivision has no effect on the distribution of genotypes. Many of the forces that affect genetic variation in panmictic populations have an influence on the degree of genetic differentiation, and many of the results will be surveyed in this chapter. Even in the “simplest” case of strictly neutral mutation, there are some intriguingly counter-intuitive results. The amount of migration among subpopulations necessary to make the population appear as one panmictic unit is surprisingly small.