Depauperated gene pools in Marmota marmota are caused by an ancient bottle neck: electrophoretic analysis of wild population from Austria and Switzerlan [Les réservoirs appauvris de gènes chez M. marmota sont dues à un ancien goulot d'étranglement : analyse électrophorétique de populations sauvages d'Autriche et de Suisse].

Résumé

Samples from 15 populations of the Alpine marmot Marmota m. marmota Linneus, 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 8430 genes exmined. The geographic variation pattern of the allele frequencies indicates genetic differentiation between autochtonous and introduced populations. No striking deviations of the genotype distributions from Hardy-Weinberg equilibrium were observed. Thus the population structure is apparently not affected by inbreeding. The obviously diminished genetic variation and the geographic pattern of allele frequencies at the two variable loci can be best explained by assuming a severe bottleneck in the recent past.