Abstract

BackgroundThe South China landmass has been characterized by a complex geological history, including mountain lifting, climate changes, and river capture/reversal events. To determine how this complexity has influenced the landmass’s phylogeography, our study examined the phylogeography of Garra orientalis, a cyprinid widely distributed in South China, using sequences from the mitochondrial DNA control region and cytochrome b gene (1887 bp) and polymorphisms of thirteen microsatellite loci.ResultsIn total, 157 specimens were collected from eight populations. All 88 mtDNA haplotypes were identified as belonging to three major lineages, and these lineages were almost allopatric in their distributions. The results of a statistical dispersal-vicariance analysis suggested that the ancestral populations of G. orientalis were distributed south of the Yunkai Mountains, including on Hainan Island. The mtDNA data revealed a strong relationship between phylogeny and geography. In the microsatellite analysis, a total of 339 alleles with an average of 26 alleles per locus were observed across thirteen microsatellite loci. A clustering algorithm for microsatellite data revealed an admixture-like genetic structure. Although the mtDNA and microsatellite data sets displayed a discordant population structure, the results of an approximate Bayesian computation approach showed that these two markers revealed congruent historical signals. The population history of G. orientalis reflects vicariance events and dispersal related to the complex geological history of South China.ConclusionOur results (i) found that the discordances between mtDNA and microsatellite markers were accounted for by admixtures; (ii) showed that the Wuzhishan and Yinggeling mountain ranges and Qiongzhou Strait were important barriers limiting gene exchange between populations on both sides; (iii) indicated that during glaciation and inter-glacial periods, the strait and continental shelves were exposed and sank, which contributed with the dispersion and differentiation of populations; and (iv) displayed that the admixtures between lineages took place in coastal populations and then colonized the tributaries of the Pearl River.

Highlights

  • The South China landmass has been characterized by a complex geological history, including mountain lifting, climate changes, and river capture/reversal events

  • Mitochondrial DNA diversity A total of 65 D-loop haplotypes (751 bp, 48 phylogenetically informative sites: KR698422–KR698486) and 31 cytochrome b haplotypes (1136 bp, 12 phylogenetically informative sites; KR698391–KR698421) were obtained for 157 G. orientalis specimens from the eight populations analyzed (Table 1; Fig. 1)

  • Incomplete lineage sorting vs. admixture According to the spatial genetic structure of G. orientalis (Figs 2 and 3), our study found that the distributions of mtDNA lineages were restricted by geological barriers (Fig. 2), but the microsatellite clusters were not (Fig. 3)

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Summary

Introduction

The South China landmass has been characterized by a complex geological history, including mountain lifting, climate changes, and river capture/reversal events. A vast geographical area with complex geology, is divided into five major geographical regions according to the essential geo-historical events and ichthyofauna [1]. These regions are as follows: (1) North China, (2) West China, (3) Mongolia–Ningxia, (4) East China and (5) South China. The Zhejiang-Fujian subregion, including the southeastern coastal districts, is located in southeastern China, south of the Yangtze River, north of the Pearl River, and east of the Wuyi Mountains. A study of the evolutionary history of Cobitis sinensis (Sauvage & Dabry de Thiersant, 1874) supported this hypothesis [5]

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