Geographic isolation is among the most important factors initiating speciation in mammals. The narrow-headed vole Lasiopodomys gregalis is a widely distributed species in steppe habitats of South Siberia that are highly fragmented by mountain ranges. There are three major mostly allopatric mitochondrial lineages of L. gregalis described throughout the distribution range that most plausibly split in the Middle Pleistocene. This study applies the analysis of five microsatellite loci and species distribution modelling to understand the patterns of isolation and migration between L. gregalis populations in South Siberia and in particular in Tuva basin where all three lineages occur simultaneously. Microsatellite analysis supported the population differentiation revealed previously, with three clusters corresponding to mitochondrial lineages and indicated that gene flow between them is strongly limited. There were only traces of hybridisation in the population near the contact zone of lineages B and C. SDM analysis predicted only a small number of potential contact zones between L. gregalis lineages and barriers corresponding to landscape heterogeneity. We presume that the forested mountain ranges act as the main insurmountable barriers to gene flow between major genetic lineages of L. gregalis.

地理隔离是引发哺乳动物物种形成的最重要因素之一。窄头田鼠Lasiopodomys gregalis是在南西伯利亚的草原生境中分布广泛的物种，被山脉高度分散。有三大主要异域线粒体谱系L. gregalis贯穿在中更新世最振振有词分裂的分布范围描述。这项研究应用五个微卫星基因座和物种分布模型的分析，以了解L. gregalis之间的隔离和迁移模式西伯利亚南部，特别是图瓦盆地的所有三个世系同时发生。微卫星分析支持先前揭示的种群分化，具有对应于线粒体谱系的三个簇，并表明它们之间的基因流动受到强烈限制。在谱系B和C的接触区附近的种群中只有杂交的痕迹。SDM分析预测，L。gregalis谱系和与景观异质性相对应的障碍之间只有少量潜在的接触区。我们假定的森林山脉作为主要的遗传谱系之间的主要不可逾越的障碍基因流L. gregalis。