长江上游5个草鱼群体的遗传多样性

Genetic diversity of five Ctenopharyngodon idella populations in the upper reaches of the Yangtze River

为了了解三峡大坝、向家坝等水电工程建设后长江上游草鱼的遗传多样性和群体结构,利用线粒体Cyt b基因分析了长江上游邵女坪、巴南、万州、太平溪、合川等5个草鱼群体的遗传多样性、种群历史动态及群体之间的遗传分化。结果显示,长江上游草鱼群体的遗传多样性较低,5个群体的单倍型多样性为0.618~0.800,核苷酸多样性为0.088%~0.112%。5个群体的错配分析图呈单峰分布,表明长江上游草鱼在历史上发生过瓶颈效应和种群扩张。分子方差变异分析(AMOVA)显示草鱼群体的遗传变异主要来自群体内部(96.96%),仅有3.04%的变异来自群体之间。群体之间的遗传分化指数FST显示邵女坪群体和合川群体之间存在显著的遗传分化,其余群体之间遗传分化不显著。

Mitochondrial Cytochrome b region(Cyt b)analysation were used in this experiment to understand the genetic diversity and population structure of Ctenopharyngodon idella in the upper reaches of the Yangtze River after the construction of hydropower projects such as Three Gorges Dam and Xiangjiaba Dam.Meanwhile,the genetic diversity and historical population dynamics within the population and genetic differentiation between populations of C.idella from Shaonvping,Banan,Wanzhou,Taipingxi and Hechuan were studied.The results showed that the haplotype diversity ranged from 0.618 to 0.800 for the five populations,and the nucleotide diversity ranged from 0.088%to 0.112%,which indicated the low genetic diversity of C.idella in the upper reaches of the Yangtze River.Mismatch distribution for each of the five populations exhibited a unimodal distribution,which indicated these five populations had suffered from bottleneck effect and population expansion.The AMOVA analysis revealed that 96.96%of the genetic variation occurred within populations,whereas 3.04%of the genetic variation occurred among populations,which suggested significant genetic variation occurred within populations.Pairwise FST values between the populations suggested that there was no significant genetic differentiation between every two populations except the combination between Shaonvping and Hechuan populations.It was suggested to strengthen the protection of C.idella germplasm resources in the Yangtze River,and adopt measures such as bans on fishing,habitat restoration,and increase captive breeding and reintroduction to promote the restoration of C.idella resources and protection of genetic diversity.Given the significant genetic differentiation between the Shaonvping and Hechuan populations,this species should be protected as different management units.