Genomic Phylogeography of Gymnocarpos przewalskii (Caryophyllaceae): Insights into Habitat Fragmentation in Arid Northwestern China

Hong-Xiang Zhang,Qian Wang,Su-Wen Jia

doi:10.3390/d12090335

Abstract

Extensive range of deserts and gobis (rocks) had promoted habitat fragmentation of species in arid northwestern China. Distribution of endangered Gymnocarpos przewalskii Maxim. covers most of gobis (rocks) and desert terrain across arid regions of northwestern China. In the present study, we had employed genomic phylogeographical analysis to investigate population structure of G. przewalskii and test the effect of environmental conditions on spatial pattern of genetic diversity. Results showed four groups were identified from east to west: Edge of the Alxa Desert, Hexi Corridor, Hami Basin, and North edge of the Tarim Basin. Genetic diversity was at an equal level among four groups. General linear model (GLM) analysis showed spatial pattern of genetic diversity was significant correlated with three habitat variables including habitat suitability at present (Npre) and last glacial maximum (LGM) (NLGM) periods, and locality habitat stability (NStab). It concluded that habitat fragmentation had triggered lineage divergences of G. przewalskii in response to long-term aridification. Genome-wide single nucleotide polymorphisms (SNPs) could increase the ability of clarifying population structures in comparison with traditional molecular markers. Spatial pattern of genetic diversity was determined by fragmented habitats with high habitat suitability (Npre and NLGM) and stability (NStab). At last, we propose to establish four conservation units which are in consistent with the population grouping to maintain the genetic integrity of this endangered species.

Highlights

Habitat fragmentation played an important role in the process of terrestrial species evolution.Many types of fragmentation were shown in the species natural habitats, including islands, mountain tops, and landscape fragment [1,2]
Based on the sampling strategy and molecular approaches, we aimed to (1) clarify population structure of G. przewalskii in response to habitat fragmentation, (2) test the effect of historical and current environmental conditions on the spatial pattern of genetic diversity for G. przewalskii populations with fragmented distributions, (3) identify conservation units to maintain the genetic integrity of this endangered species
G. przewalskii using the cpDNA fragments, nrITS, and SSR markers [17]. They approved to divide the range of G. przewalskii into four geographical groups, distinct genetic divergence was not obtained among the four groups using the three types of traditional molecular markers

Summary

Introduction

Many types of fragmentation were shown in the species natural habitats, including islands, mountain tops, and landscape fragment [1,2]. These fragmented habitats usually displayed complex effects of genetic structure among intraspecific populations. Fragmented landscape could led to the loss of rare alleles in some small populations [6]. Another type of fragmentation exists in arid lands. Investigating the course of species evolution could make us well understand the influences of habitat fragmentation in arid lands

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Discussion

Conclusion