Ecological Indicators (Jun 2022)
Pleistocene climate-driven diversification of plateau zokor (Eospalax baileyi) in the eastern Qinghai-Tibet Plateau
Abstract
Glacial oscillations and associated tectonic processes during the middle-late Pleistocene are thought to have created a unique pattern of species distribution diversity in the Qinghai-Tibet Plateau (QTP). As a subterranean rodent endemic to the QTP, the impact of these geological events on the genetic diversity and demographic history of plateau zokors (Eospalax baileyi) is worth exploring. In this study, genetic diversity analyses were performed based on two mitochondrial DNA regions and microsatellite markers, representing 370 individuals from five populations on a large scale and six populations on two small scales in the eastern QTP. On a large scale, both mitochondrial DNA and microsatellite markers implied substantial genetic diversity and strong differentiation of the five populations. All sampled populations showed only unique haplotypes and lacked shared haplotypes, revealing the isolated nature of most populations. The genetic differentiation of the plateau zokor was in line with that of the isolate by distance (IBD) model. Mismatch distribution and Bayesian skyline analysis suggested recent demographic expansions highly consistent with glaciation events, and BEAST divergence analysis unveiled southward divergence events originating from the northern populations of the eastern QTP. The genetic structure of the five populations was almost singular. On a small scale, all the populations showed high genetic diversity. However, the analysis of molecular variation (AMOVA) showed less variation among populations; the genetic differentiation of the populations no longer conformed to IBD model, and the genetic information among populations was more heterogenous and similar to those of each other. Overall, our research revealed the genetic differentiation of plateau zokor driven by quaternary climatic oscillation and the variations in the genetic diversity of the plateau zokor at different geographical scales.
