Pleistocene climate change and phylogeographic structure of the Gymnocarpos przewalskii (Caryophyllaceae) in the northwest China: Evidence from plastid DNA, ITS sequences, and Microsatellite.

Shu‐Wen Jia,Ming‐Li Zhang

doi:10.1002/ece3.5113

Abstract

Northwestern China has a wealth of endemic species, which has been hypothesized to be affected by the complex paleoclimatic and paleogeographic history during Quaternary. In this paper, we used Gymnocarpos przewalskii as a model to address the evolutionary history and current population genetic structure of species in northwestern China. We employed two chloroplast DNA fragments (rps16 and psbB‐psbI), one nuclear DNA fragment (ITS), and simple sequence repeat (SSRs) to investigate the spatial genetic pattern of G. przewalskii. High genetic diversity (cpDNA: h S = 0.330, h T = 0.866; ITS: h S = 0.458, h T = 0.872) was identified in almost all populations, and most of the population have private haplotypes. Moreover, multimodal mismatch distributions were observed and estimates of Tajima's D and Fu's FS tests did not identify significantly departures from neutrality, indicating that recent expansion of G. przewalskii was rejected. Thus, we inferred that G. przewalskii survived generally in northwestern China during the Pleistocene. All data together support the genotypes of G. przewalskii into three groups, consistent with their respective geographical distributions in the western regions—Tarim Basin, the central regions—Hami Basin and Hexi Corridor, and the eastern regions—Alxa Desert and Wulate Prairie. Divergence among most lineages of G. przewalskii occurred in the Pleistocene, and the range of potential distributions is associated with glacial cycles. We concluded that climate oscillation during Pleistocene significantly affected the distribution of the species.

Highlights

Complex paleoclimatic and paleogeographic history has left a pro‐ found influence on the distribution and the spatial genetic structure of plant species in the Northern Hemisphere (Hewitt, 2000)
In the populations of many desert plants have higher total genetic diversity but lower within populations genetic diversity, and allopatric divergence has generally been found in desert plants, for example, Ribes meyeri (Xie & Zhang, 2013), Hexinia polydichotoma (Su, Zhang, & Cohen, 2012), Helianthemum songaricum (Su, Zhang, & Sanderson, 2011), Nitraria sphaerocarpa (Su & Zhang, 2013), and Atraphaxis frutescens (Xu & Zhang, 2015)
We aimed to address the following questions: (1) to reveal the evolutionary history and (2) ex‐ plore current population genetic structure of G. przewalskii from in northwestern China

Summary

| INTRODUCTION

Complex paleoclimatic and paleogeographic history has left a pro‐ found influence on the distribution and the spatial genetic structure of plant species in the Northern Hemisphere (Hewitt, 2000). JIA and ZHANG of influence of history on the Chinese flora and fauna, a plethora of phylogeographic researches have focused on the Sino‐Japanese Floristic Region and Qinghai‐Tibet Plateau in recent decades (Li, Yue, Sun, & Qian, 2012; Li et al, 2013; Poudel et al, 2015; Ye, Zhu, Chen, Zhang, & Bu, 2014) Few such studies focusing on plant species from northwestern China have been reported (Gao, Meng, & Zhang, 2014; Zhang & Zhang, 2012a). Previous phylogeographic studies of G. przewalskii (Ma, Zhang, & Sanderson, 2012) based on chloroplast genetic data alone showed the species to have high levels of genetic variation, especially in the western Tarim Basin, the Hami Basin, the Liuyuan region in western Gansu, and at the easternmost end of the dis‐ tribution of the species.

| MATERIALS AND METHODS

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| DISCUSSION

Findings

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