TESTING DIFFERENTIATION IN DIPLOID POPULATIONS

We examine the power of different exact tests of differentiation for d iploid populations. Since there is not necessarily random mating withi n populations, the appropriate hypothesis to construct exact tests is that of independent sampling of genotypes. There are two categories of tests, F-ST-estimator tests and goodness of fit tests. In this latter category, we distinguish ''allelic statistics'', which account for th e nature of alleles within genotypes, from ''genotypic statistics'' th at do not. We show that the power of F-ST-estimator tests and of allel ic goodness of fit tests are similar when sampling is balanced, and hi gher than the power of genotypic goodness of fit tests. When sampling is unbalanced, the most powerful tests are shown to belong to the alle lic goodness of fit group.