Microsatellite analysis of population structure and genetic differentiation within and between populations of the root vole, Microtus oeconomus in the Netherlands

Eight microsatellite markers for the root vole (Microtus oeconomus) were de veloped to assess the amount of genetic variation for nine Dutch root vole populations from four different regions, and to evaluate the degree of diff erentiation and isolation. All eight microsatellite loci were found to be h ighly variable with observed heterozygosity values ranging from 0.61 to 0.8 2. These values are similar to those observed for more distant populations from Norway, Finland and Germany. Therefore, the populations seem not parti cularly depauperate of genetic variation at the microsatellite level. Genet ically, the Dutch populations were found to have diverged considerably. Pai rwise comparisons of all populations studied revealed Fs, values significan tly greater than zero for most comparisons. However the magnitude of these values considerably depends on the compared population pair The level of di fferentiation between local populations within Dutch regions is generally s ignificantly lower than the differentiation between Dutch regions. The leve l of differentiation between Dutch regions, however, is not significantly d ifferent from that between populations of larger geographical distance. Thi s implies that the regional Dutch populations are both isolated from each o ther and from other European populations. The observation that even local p opulations show low but significant genetic differentiation may be indicati ve for progressive isolation of these populations.