用微卫星技术研究珠江流域三个野生大眼鳜群体的遗传多样性

采用微卫星标记技术,探讨了广西右江、左江及红水河三江段野生大眼鳜群体的遗传多样性。采用生物信息学方法,自主开发了4对大眼鳜微卫星DNA引物,此外,还从28对鳜属微卫星通用引物中筛选出15对,19对标记均表现为高度多态性。对32尾右江(YJ)、35尾左江(ZJ)及36尾红水河(HSH)三地理群体野生大眼鳜进行遗传多样性分析,总群体的固定指数Fix范围为0.001 4~1.000,表明19个位点在总群体内表现为杂合子缺失,其对环境的应对能力有所下降。遗传参数统计结果表明,总群体观测等位基因数(Na=19.4737)、香农指数(I=2.399 8)、平均杂合度(Ave Het=0.720 6)、多态信息含量(0.447PIC0.947)均显示:在哈温平衡下,大眼鳜3群体遗传多样性丰富;但3群体遗传多样性存在差异,红水河群体的遗传多样性比左江群体、右江群体的遗传多样性丰富,左江和右江群体的遗传多样性水平较为接近。群体间遗传分化水平较大(0.15群体间近交系数Fst=0.153 90.25),15.39%的遗传变异来自于群体间,84.61%的遗传变异来自于群体内,群体内近交系数Fis为0.576 1,各座位的基因流Nm分布范围较广(0.147 4~8.909 1),平均Nm值为1.374 5,表明3群体间属于中等遗传分化水平,基因流基本顺畅,群体内的近交系数较高,容易引起遗传结构的变化。基于Nei's遗传距离的聚类分析显示左江群体与右江群体首先聚为一支,再与红水河聚为一支,符合其在地理位置上的关系。

Genetic Diversity Among Three Wild Populations of Siniperca kneri in the Pearl River by Microsatellite Technology

Genetic diversity of three wild populations of 〖WTBX〗Siniperca kneri〖WTBZ〗 from Youjiang River,Zuojiang River and Red Water River  was studied by microsatellite DNA molecular markers. Total 19 pairs of highly polymorphic microsatellite primers of S. kneri, including 4 pairs exploited autonomously by bioinformatics and 15 pairs screened from 28 pairs of general primers, were adopted for this study. Analyzing 19 microsatellite locis for three populations, and total 102 individuals, Fixation Index among 3 populations varied from 0.001 4 to 1.000 0 showed the loss of heterozygosity, which leaded to lowering its response to the environment. Observed Number of Alleles (Na=19.473 7) , Shannons Information Index (I=2.399 8), Average Heterozygosity (Ave_Het =0720 6), and Polymorphism Information Content (0.447＜PIC＜0.947) were indicated the abundant genetic diversity among the three populations under Hardy-Weinberg equilibrium. But there was some differentiation among the three populations: Average Heterozygosity of Red Water River was the highest（Ave_Het=0.771 5）, and that of Zuojiang River and Youjiang River were lower and similar (0.692 1、0.698 3). The Genetic Differentiation Index (Fst) among 3 populations was 0.153 9, between 0.15 and 0.25, 84.61% of which was contributed by intra-population and 15.39% by inter-population. Fis Value was 0.576 1. Gene Flow (Nm) of all locis were widely varied between 0.147 4 and 8.909 1, and its average was 0.795 7, which indicated there was the medium genetic differentiation level among populations, and gene flow was smooth in general. Their inbreeding coefficient was relatively high which changed easily genetic structure of population. The UPGMA dendrogram based on the Nei''s genetic distance suggested that the populations of Zuojiang River and Youjiang River clustered firstly and then did with that of Red Water River. The dendrogram relationship and genetic distance of three populations are closely linked with geography distribution.