伊犁河流域不同群体伊犁裂腹鱼遗传差异分析

摘要

IlischizothoraxSchizothorax pseudaksaiensisfoundonlyinIliRiverinXinjiangisanindigenousandecologicallysensitive species in Ili R iver basin. In the past years, the population of S. pseudaksaiensis w as sharply declined due to overfishing and the changes in habitats by exploitation of hydraulic projects. A total of 54 individuals w ere collected from four sam pling sites in the Ili River,aligned1109bpsequenceswereanalyzedinthemitochondrialDNA cytochromebgenetoevaluatethegeneticstructureofS. pseudaksaiensis and im pactfactors.Sixteen haplotypes w ere defined in 54 individuals,the m axim alvalue in Y am adu river population (YJ)andtheminimum inQiapuqihaireservoirpopulation (YQ).Thetwocladeswereobservedinbothmolecularphylogenetictree and haplotype netw ork,and haplotypes in differentpopulations w ere found to be interspersed.The average genetic distances revealed that the differentiation w as still intraspecific in four populations, not subspecies level. T he differentiation tendency of the haplotypes w as involved in the separation effect of dam s. From the perspective view of conservation biology, different m anagem ent strategies should be adopted to the tw o groups ofS.pseudaksaiensis.%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。