伊犁河流域不同群体伊犁裂腹鱼遗传差异分析

伊犁裂腹鱼（Schizothorax pseudaksaiensis）仅分布于新疆伊犁河流域，是该流域典型的土著种和生态敏感种。近年来，过度捕捞及水利工程开发使栖息地环境改变，种群数量急剧减少。本研究分析了伊犁河流域4个采样点共计54尾伊犁裂腹鱼线粒体DNA细胞色素b基因（长度为1109bp）的序列，探讨了伊犁裂腹鱼遗传结构及其影响因素。54尾个体共定义了16种单倍型，其中雅玛渡采样点群体（YJ）享有单倍型的数量最多，而恰普其海水库群体（YQ）享有单倍型的数量最少。单倍型分子系统树和中介网络图均分为两支，不同群体间单倍型交叉出现。平均遗传距离表明，4个伊犁裂腹鱼群体的遗传分化为种内个体间差异，尚未达到亚种水平。伊犁裂腹鱼单倍型分布的分化可能与大坝的阻隔效应有关。建议对两个类群伊犁裂腹鱼采取不同的管理策略加以保护。

Genetic Differentiation of Ili Schizothorax（Schizothorax pseudaksaiensis）Populations in Ili River Basin

Ili schizothorax Schizothorax pseudaksaiensis found only in Ili River in Xinjiang is an indigenous and ecologically sensitive species in Ill River basin. In the past years, the population of S. pseudaksaiensis was sharply declined due to overfishing and the changes in habitats by exploitation of hydraulic projects. A total of 54 individuals were collected from four sampling sites in the Ili River, aligned 1109 bp sequences were analyzed in the mitochondrial DNA cytochrome b gene to evaluate the genetic structure of S. pseudaksaiensis and impact factors. Sixteen haplotypes were defined in 54 individuals, the maximal value in Yamadu river population （YJ） and the minimum in Qiapuqihai reservoir population （YQ）. The two clades were observed in both molecular phylogenetic tree and haplotype network, and haplotypes in different populations were found to be interspersed. The average genetic distances revealed that the differentiation was still intraspecific in four populations, not subspecies level. The differentiation tendency of the haplotypes was involved in the separation effect of dams. From the perspective view of conservation biology, different management strategies should be adopted to the two groups of S. pseudaksaiensis.