Comparison of differentiation pattern at allozyme and microsatellite loci in Parnassius mnemosyne (Lepidoptera) populations

A recent review on the use of microsatellites in Lepidoptera has showed that their identification is difficult in this group, which may explain the limited use of these markers in this taxon. In this study on Parnassius mnemosyne, the results obtained for three microsatellite and three allozyme loci are compared. With both categories of markers, (i) deficit of heterozygotes compared with Hardy-Weinberg expectations was found in many populations, and (ii) strong differentiation was observed between regions, contrasting the rather homogeneous gene pools found within regions. The use of dry samples of museum collections in microsatellite analyses enabled us to study changes in allele frequencies over time in a small, isolated population. The results supported our earlier finding with allozymes that the small populations have been subject to strong genetic drift. Since essentially the same results were obtained with the allozyme and microsatellite markers, this study indicates that the potential advantages of microsatellites over allozymes in studies of population structure are counterbalanced in species where only a small number of microsatellite loci are available.