Impact of Orogeny and Environmental Change on Genetic Divergence and Demographic History of Dipus sagitta (Dipodoidea, Dipodinae) since the Pliocene in Inland East Asia

Abstract

Inland East Asia encompasses particular landscapes, including discontinuous large deserts isolated by mountains, and these landscapes have been greatly impacted by the uplift of the Qinghai-Tibetan Plateau (QTP) since the Pliocene. However, little research has been performed on the impact of desertification on the evolutionary history of animals in this area. We examined a widespread desert rodent species, Dipus sagitta, to better understand the influences of geological events on the evolutionary history and phylogeographic patterns. We sequenced two mitochondrial genes and three nuclear genes from 237 individuals collected from 43 populations across inland East Asia. Phylogenetic, network, intraspecific delimitation, and population structure analyses identified a structured pattern of geographic differentiation with six well-defined evolutionary clades. High mountains (such as the Tianshan Mountains) and important climate demarcation lines (such as the 200 mm isohyet) were inferred as genetic barriers among the six clades by BARRIER analysis. The most recent common ancestor of D. sagitta was estimated to have existed in late Miocene, and the first clade was estimated to have diverged at c. 7.57 Ma, whereas the later clade diversified rapidly at approximately 2.56–1.53 Ma during the Pleistocene. Demographic analyses suggested different demographic histories among the distinct clades, and the continuous expansion that occurred during the climate oscillation period appeared to be more closely related to the increasing aridification caused by orogeny rather than climate oscillation.