Genetic structure of Brandt's vole (Lasiopodomys brandtii) populations in Inner Mongolia, China, based on microsatellite analysis

Brandt's vole (Lasiopodomys brandtii) distribution is discontinuous in Inner Mongolia with some populations isolated from others. Recently, some isolated populations have suffered extinction, and the factors responsible remain elusive. Genetic drift is one of the processes affecting population genetic differentiation, and can play a substantial role in the divergence of small, isolated populations. Using seven microsatellite markers, we genotyped four geographically isolated populations of Brandt's vole, all of which exhibit episodic fluctuations in population density. The results showed a strong genetic differentiation among the geographically distinct populations (total F (ST) = 0.124) and in particular, one population (Zhengxiangbaiqi) was isolated from all others (F (ST) values were greatest between Zhengxiangbaiqi and other populations). Furthermore, high levels of inbreeding (F (IS) values ranged from 0.205 to 0.290) within each distinct population suggest that inbreeding has and is likely occurring in Brandt's vole populations. These processes can decrease average individual fitness and consequently increase the risk of extinction of the species.