长江上游中华金沙鳅和短身金沙鳅线粒体遗传多样性研究

为了解中华金沙鳅(Jinshaia sinensis)及短身金沙鳅(J.abbreviate)遗传多样性,本研究采用线粒体DNA控制区序列,对长江上游巴南、江津、合江、宜宾、犍为、巧家、宁南和攀枝花等8个群体的中华金沙鳅(Jinshaia sinensis)及巴南、合江和犍为3个群体的短身金沙鳅(J.abbreviate)的遗传多样性进行研究。结果显示:中华金沙鳅和短身金沙鳅的遗传结构存在差异,中华金沙鳅的遗传多样性较高,单倍型多样性(Hd)和核苷酸多样性(Pi)分别为0.999和0.0182;而短身金沙鳅的遗传多样性水平较低(Hd:0.411,Pi:0.0005)。分子变异方差分析(AMOVA)显示两种鱼均无显著地理遗传分化,但单倍型系统发育树和网络结构图揭示了中华金沙鳅存在群体内遗传分化,形成三个谱系,表明缺乏长期亚群体隔离和高水平基因流。中性检验和Bayesian skyline plot(BSP)结果表明,中华金沙鳅在历史上曾发生过群体扩张事件,扩张时间约在10万~17万年前。

Genetic diversity between Jinshaia sinensis and J.abbreviata in the upper reaches of Yangtze River based on mitochondrial DNA

Jinshaia sinensis and J.abbreviata are endemic fishes in the upper reaches of the Yangtze River.J.sinensis is one of the protected species of the National Nature Reserve for the rare and endemic fishes in the upper reaches of the Yangtze River.In recent years,the construction of waterpower dams in the upper reaches of the Yangtze River had seriously threatened to fish habitat.Information on population genetics is useful for resource conservation issues.In this study,we used mitochondrial control region sequences to evaluate the genetic diversity of the two fishes.Samples were collected from Banan,Jiangjin,Hejiang,Yibin,Qianwei,Qiaojia,Ningnan and Panzhihua sections in the upper reaches of the Yangtze River and Jinsha River.The results showed disparate genetic patterns in these two species.The genetic diversity of J.sinensis was high with haplotype diversity(Hd)and nucleotide diversity(Pi)being 0.999 and 0.0182,respectively.In contrast,Hd and Pi of J.abbreviate were 0.411 and 0.0005,respectively,which indicated low level of genetic diversity.Analysis of molecular variance(AMOVA)both showed no significant geographically structure for two fishes.However,haplotype phylogenetic trees and network revealed shallow three lineages within J.sinensis populations,indicating a lack of long-term isolation of subpopulations and a high level of gene flow.The neutral test and Bayesian skyline plot(BSP)showed that J.sinensis had experienced historical population expansion in the(10~17)×104 years ago.Considering the development of ladder hydropower in the upper reaches of the Yangtze River,we suggest that the monitoring of resources and genetic diversity should be focused in the future.