GENETIC VARIATION IN THE AFRICAN VLEI RAT OTOMYS IRRORATUS (MURIDAE: OTOMYINAE)

Abstract

ABSTRACT Starch gel electrophoresis was used to analyse genetic variation at 24 enzyme and protein loci in 12 South African populations of vlei rats Otomys irroratus. Mean heterozygosity ([Hbar]: 0.071) was relatively high for a mammal. Allelic variation within populations conformed to Hardy-Weinberg expectations, and the mean value for Wright's F IS statistic (0.048) indicated no evidence of inbreeding within populations. There was significant local differentiation in allelic frequencies (Wright's F ST = 0.375). However, genetic distances between populations were low (mean for Nei's D = 0.034), and cluster analysis of genetic distances failed to identify groups consistent with geographical position or karyotypic differences between populations. A single population (Hogsback, eastern Cape), bearing a chromosomal tandem fusion and demonstrating a high measure of reproductive isolation, showed no allozymic differences from other populations, suggesting that chromosomally-mediated speciation may precede phen...