Genic Variation of the Rock Vole, Microtus chrotorrhinus

Abstract

Genic variation and genic structure of three populations of Microtus chrotorrhinus and two of Microtus pennsylvanicus were analyzed using horizontal starch gel electrophoresis. The mean heterozygosity (H = 0.145) for 18 proteins encoded by 25 structural loci in M. pennsylvanicus was higher than that reported for most mammals. The mean heterozygosity observed in M. chrotorrhinus (H̄ = 0.049) was consistent with the mean value reported for rodents, but not with values reported for isolated populations of mammals. Although the difference in the level of genic variation maintained in M. chrotorrhinus and M. pennsylvanicus may reflect different rates of gene flow among populations, the differences in reproductive potential, effective population size, and frequency of bottleneck may account for the observed difference.