The rate of allelism of lethal genes in a geographically structured population

Abstract

The expected rate of allelism, E[I(x)], of lethal genes between two colonies with distance x in a structured population is studied by using one- and two-dimensional stepping-stone models. It is shown that E[I(x)] depends on the magnitude of selection in heterozygous condition (h), the rate of migration among adjacent colonies (m), the number of loci which produce lethal mutations (n) and the effective population size of each colony (N) E[I(x)] always decreases with distance x. The rate of decrease is affected strongly by the magnitude on m. The rate of decrease is faster when m is small. E[I(x)] also decreases with increasing N and n. The effect of h on E[I(x)] is somewhat complicated. However, E[I(O)] is always smaller when h is small than when it is large. For large x, a formula is presented.