Depauperated gene pools in Marmota m. marmota are caused by an ancient bottle neck: electrophoretic analysis of wild populations from Austria and Switzerland

Abstract

Samples from 15 populations of the Alpine marmots Marmota m. marmota (Linnaeus 1758) were surveyed electrophoretically for allozyme variation. Only 2 out of 50 enzyme loci showed polymorphism. Average heterozygosity was found to be low with 1.2%. No rare alleles were detected among the 8430 genes examined. The geographic variation at the two polymorphic loci (Pep-1 and Sod-1) was analysed in more detail. The distribution pattern of teh allele frequencies indicates genetic differeniation between autochthonous and introduced populations. No striking deviations of the genotype distributions from Hardy- Weinberg equilibrium were observed. Thus the population structure is apparently no affected by inbreeding. The obviously diminished genetic variation and the geographic pattern of the allele frequencies at the two variable loci can be best explained by assuming a severe bottleneck in the recent past