瓦氏雅罗鱼达里湖群体和乌苏里江群体的遗传多样性和遗传结构分析

Genetic variability and genetic structure of Leuciscus waleckii Dybowski in Wusuli River and Dali Lake

选用5个瓦氏雅罗鱼(Leuciscus waleckii Dybowski)微卫星标记和13个草鱼微卫星标记,对分别采自内蒙古境内的达里湖和乌苏里江抚远江段的各15尾野生瓦氏雅罗鱼个体进行STR-PCR分析。结果显示,18个微卫星标记共检测到111个等位基因,平均每个基因座扩增得到6.1667个等位基因,观测杂合度(H o)0.1000～0.9333,平均为0.5315;期望杂合度(H e)0.0966～0.9328,平均为0.6298;多态信息含量(PIC)0.0905～0.9113,平均为0.5774;乌苏里江群体的平均等位基因数和平均观测杂合度分别为5.5556和0.5778,达里湖群体的平均等位基因数和平均观测杂合度均低于乌苏里江群体的平均等位基因数和平均观测杂合度,分别为4.3889和0.4852。2个群体间的遗传距离(D c)为0.2550。个体聚类结果显示,达里湖雅罗鱼所有个体聚为一簇,乌苏里江雅罗鱼所有个体聚为一簇。群体间的遗传分化指数(F st)为0.0855,数值介于0.05～0.15,N m值为2.6749,表明这2个群体处于中等分化,存在一定程度的基因交流。对2个群体的基因型进行了Hardy-Weinberg平衡的卡方检验,结果表明两群体均在一定程度上偏离了平衡。

Leuciscus waleckii Dybowski belongs to Cypriniformes, Cyprinidae and Leuciscus, mainly distributing in Amur River, Wusuli River, Songhua River, Liaohe River, Yellow River, Luanhe River and Nenjiang River. It is a cold water species and can survive in saline-alkaline waters above pH 9.0. While, a large number of L. waleckii survive in Dali Lake, which is located in the northeast of Inner Mongolia and is a saline-alkaline lake with a salinity of 6.96 and alkalinity of 53.57 mmol/L. Using 5 microsatellite markers of L.waleckii and 13 microsatellite markers of grass carp, we analyzed genetic differences and structures of L.waleckii sampled from Wusuli River and Dali Lake. The estimates of genetic variability showed that a total of 111 alleles were detected with average of 6.166 7 at each locus. The observed heterozygosity （Ho） ranged from 0.100 0 to 0.933 3 with the mean of 0.531 5. The expected heterozygosity （He） and polymorphic information content （PIC） were 0.096 6-0.93：2 8 and 0.090 5-0.911 3,respective in Dali po L.waleckii The average number of alleles and average Ho in Wusuli River population were 5.555 6 and 0.577 8 and ation were 4.38S 9 and 0.485 2 .As described above, the levels of genetic variability were moderate in this study. But the level of genetic diversity in Dali population was slightly lower than that in Wusuli population .The protection of wildlife resources should be strengthened in the future. The genetic distance between the two populations is 0.255 0 and the genetic similarity index is 0.774 9. Individual clustering showed that all Dali individuals converged in the right branch of topology tree, and the 15 individuals of Wusuli population converged in the left branch. The values of pairwise F,t and gene flow （Nm） were also estimated for the two populations. The value of pairwise F^t is 0.085 5, Nm is 2.674 9, indicating Dali and Wusuli populations have a moderate level of differention and little gene exchange between them. Chi-square test was used to analyze the genotype based on Hardy-Weinberg equilibrium; the P value denoted that the two populations deviated equilibrium partially. [Journal of Fishery Sciences of China,2010, 17 （ 2 ） ： 228-235]