新疆草兔的种群遗传结构和亚种分化

Genetic structure and subspecies divergence of Lepus capensis in Xinjiang

新疆草兔(Lepus capensis)的群体遗传结构至今无系统的研究报道,亚种水平的分类也长期存在争议。该文测定了形态分类上的新疆草兔3个亚种共87个个体的线粒体DNA(mtDNA)控制区(control region,D-Loop)592bp的序列,经分析发现148个多态性位点,共定义了44个单倍型。新疆草兔的单倍型多样度(h,0.977±0.005)和核苷酸多样度(π,0.064±0.031)都较高,显示了较高的遗传多样性。分子变异分析(AMOVA)结果显示,4个地理群体间的显著分化可能是由地理隔离造成的。群体遗传结构分析显示,新疆草兔包含4个进化枝,并且每个进化枝都对应特定的分布区域,显示了明显的系统地理结构。该研究的结果支持形态分类上草兔西域亚种(L.c.lehmanni)的分类地位;但中亚亚种(L.c.centrasiaticus)被分为两个独立的进化枝,提示可能存在两个亚种;帕米尔亚种(L.c.pamirensis)与其他亚种间的遗传距离在13%以上,提示其可能已达到种的分化水平。

To date,the genetic structure and genetic diversity of Lepus capensis in Xinjiang has not been systematically studied at the molecular level,and its subspecies taxonomic status has been under debate for years.According to traditional morphology,there are three subspecies of L.capensis distributed in Xinjiang：L.c.centrasiaticus,L.c.lehmanni and L.c.pamirensis.In this study,we determined 592 bp D-loop sequences of 87 cape hares from Xinjiang Province.Forty-four haplotypes were defined based on 148 polymorphic sites.Both the haplotype diversity （0.977 ± 0.005） and nucleotide diversity （0.064 ± 0.031） are high.F ST P values are significantly high and no haplotype was shared among the four geographic populations,indicating that genetic differentiation among populations is significant.AMOVA shows that most of the genetic differentiation occurred among geographic groups,indicating that geographic isolation such as mountains and deserts might make an effective barrier against gene flow.Both the phylogenetic tree and median-joining network grouped 44 haplotypes into four distinct clades corresponding to four geographic areas,indicating an obvious phylogeographic pattern.Our data supported the subspecies status of L.c.lehmanni.The fact that haplotypes of L.c.centrasiaticus were grouped into two distinct clades suggests that this traditional subspecies should be considered as two subspecies.In addition,L.c.pamirensis shows a significantly higher sequence divergence compared to other subspecies,and the difference even reached the level of species.