湘西盲高原鳅遗传多样性的微卫星分析

Microsatellite analysis of population genetic diversity in Triplophysa xiangxiensis

利用筛选的16对微卫星标记对来自于湖南湘西龙山县乌龙山3个不同洞穴的盲高原鳅群体进行遗传多样性及遗传分化分析。通过计算多态信息含量、平均杂合度、等位基因数、遗传距离、基因流、F-统计量等参数,评估各盲高原鳅群体遗传多样性和各群体间遗传分化。16个微卫星标记在3个群体中共检测出83个等位基因。每个座位检测到3～8个等位基因不等。3个群体各个多态位点的平均观测杂合度分别为0.362 5～0.946 5,平均期望杂合度为0.538 6～0.906 5。3个群体多态微卫星位点的PIC分别为0.263 2、0.231 3、0.303 5,选取的16个微卫星位点中2个为高度多态,2个为低度多态,其余为中度多态。分子变异方差分析(AMOVA)结果表明,遗传变异大部分(92.84%)来自群体内,仅有7.16%的变异来自于群体间,数据表明3个群体处于未分化状态,遗传一致性较大。

The cavefish Triptophysa xiangxiensis is a species of loach belonging to family Cobitidae,order Cypriniformes.It is endemic to Longshan County of western Hunan Province of China.In this study,a total of 103 individuals from three T.xiangxiensis populations obtained from three caves in Wulongshan Mountain were studied using 16 pairs of microsatellite markers.Using polymorphism information content（PIC）,mean heterozygosity（H）,number of effective alleles and F-statistics,the genetic diversity and genetic differentiation were evaluated.A total of 83 different alleles were detected in all examined loci.The number of alleles ranged from 3 to 8,with an average number of about 5 per locus.The observed（Ho）and expected heterozygosity（He）ranged from 0.362 5 to 0.946 5 and from 0.538 6 to 0.906 5,respectively.The polymorphism information content for these three populations were 0.263 2,0.231 3,0.303 5.The results from this study indicated that two of the selected 16 microsatellite loci were high polymorphic and two loci were low polymorphic,the other twelve microsatellite loci showed moderate polymorphic.The analysis of molecular variance（AMOVA）indicated that almost majority of the variance in the T.xiangxiensis was within stocks（92.84%）,and 7.16% was among stocks.The result of AMOVA,F-statistics,Nei＇s genetic distance and genetic identity indicated that genetic difference was relatively small and genetic differentiation was low,with high genetic identity between both populations.The information obtained in this study will contribute to the conservation of this endangered T.xiangxiensis species.