The influence of late pleistocene mountain glaciations on the genetic differentiation of long-tailed ground squirrel (Urocitellus undulatus)

Abstract

Long-tailed ground squirrel (Urocitellus undulatus) is a polytypic species with a wide distribution from the Tien Shan to the Amur River region. Previously, considerable genetic differentiation between eastern and western populations of this species was demonstrated. Moreover, the greatest differences were observed in the western part of the range located in Central Asia, the region that was subjected to repeated glaciations in the past and represents one of the centers of the ground squirrel secondary diversification. The analysis of polymorphism of the mitochondrial DNA control region was carried out on long-tailed ground squirrels living in the northern part of Central Asia, on the territory of the Altai Mountains (45 individuals from 23 localities). The presence of two genetically differentiated (7.7% differences) and geographically separated lineages (western and eastern) was revealed. The data obtained disprove the hypothesis on unidirectional, from west to east, colonization of the Altai Mountains after the end of the last glacial maximum and show the two pathways of the ground squirrel colonization of the Altai, from both western and eastern refugia.