Impacts of seed and pollen flow on population genetic structure for plant genomes with three contrasting modes of inheritance

The classical island and one-dimensional stepping-stone models of populatio n genetic structure developed for animal populations are extended to hermap hrodite plant populations to study the behavior of biparentally inherited n uclear genes and organelle genes with paternal and maternal inheritance. By substituting appropriate values for effective population sizes and migrati on rates of the genes concerned into the classical models, expressions for genetic differentiation and correlation in gene frequency between populatio ns can be derived. For both models, differentiation for maternally inherite d genes at migration-drift equilibrium is greater than that for paternally inherited genes, which in turn is greater than that for biparentally inheri ted nuclear genes. In the stepping-stone model, the change of genetic corre lation with distance is influenced by the mode of inheritance of the gene a nd the relative values of long and short-distance migration by seed and pol len. In situations where it is possible to measure simultaneously F-st for genes with all three types of inheritance, estimates of the relative rates of pollen to seed flow can be made for both the short- and long-distance co mponents of migration in the stepping-stone model.