华南地区大刺鳅的遗传结构与群体动态历史研究

Genetic structure and demographic history of Mastacembelus armatus in southern China

为掌握华南地区大刺鳅(Mastacembelus armatus)的遗传种质资源现状,并为其管理和保护提供科学依据,采集了华南地区7个独立水系的16个地理群体共计140尾大刺鳅样本,基于Sanger测序获得了2个线粒体基因(COI和Cytb),综合多种分析方法对其遗传结构和群体动态史展开研究。结果表明,华南地区大刺鳅群体形成了3个谱系(I、II和III),分化时间介于0.596~0.676 Ma(百万年前)。此外,单倍型网状图发现不同谱系群体存在共域分布的现象,并提示海南岛群体与大陆群体之间可能存在两条扩散路线。群体遗传分析发现大刺鳅群体间存在显著的遗传分化(F_(ST)=0.676,P<0.001),并且符合距离隔离模式(R=0.463,P=0.001),暗示空间距离是造成大刺鳅遗传分化的一个重要因素。种群动态历史分析表明,大刺鳅群体可能在0.025 Ma经历了种群扩张事件。

In order to understand the genetic resources of Mastacembelus armatus populations in southern China,and to provide an important scientific basis for their management and protection,we collected 140 individuals from 16 geographical populations from seven independent river systems in southern China and sequenced two mitochondrial genes(COI and Cytb)via PCR amplification and Sanger sequencing,and finally revealed the genetic structure and demographic history of M.armatus populations by phylogenetic analysis,haplotype network,population genetic analysis and Bayesian skyline plot.The results show that M.armatus populations consisted of three lineages(I,II and III)and split between 0.596 and 0.676 million years ago(Ma).Haplotype network shows that there was a common domain distribution among different lineages,and suggests that there might be two diffusion routes between Hainan Island population and mainland population.Population genetic analysis finds significant genetic differentiation(F_(ST)=0.676,P<0.001)and isolation by distance pattern(R=0.463,P=0.001)among M.armatus populations,implying that spatial distance was an important factor for genetic differentiation of M.armatus.Demographic analysis shows that M.armatus populations experienced population expansion at 0.025 Ma.