Abstract:
Evolutionary consequences of natural selection, migration, genotype-environment interaction, and random genetic drift on
interpopulation variation and covariation of quantitative characters are analysed in terms of a selection model that partitions
natural selection into directional and stabilizing components. Without migration, interpopulation variation and covariation depend mainly on the pattern and intensities of selection among populations and the harmonic mean of effective population sizes. Both transient and equilibrium covariance structures are formulated with suitable approximations. Migration reduces the
differentiation among populations, but its effect is less with genotype-environment interaction. In some special cases of
genotype-environment interaction, the equilibrium interpopulation variation and covariation is independent of migration.