斑鳜不同地理群体遗传变异的AFLP分析

GENETIC VARIATION OF SINIPERCA SCHERZERI STEINDACHNER FROM DIFFERENT GEOGRAPHICAL POPULATIONS BY AFLP ANALYSIS

斑鳜(Siniperca scherzeriSteindachner)为东亚地区特有的淡水名贵经济鱼类。受生态环境破坏和渔业捕捞过度的影响,斑鳜野生资源已呈下降趋势。为探明我国斑鳜不同地理群体的遗传背景,采用AFLP分子标记技术研究了鸭绿江、海河、长江、钱塘江、闽江、西江6个地理群体的遗传特征和群体分化。斑鳜65尾个体中,8对引物组合共扩增出211条带,其中多态性条带126条,多态比例为59.7%,并观察到一些群体的特异性条带。群体内的遗传变异以长江群体最大(6.7%),群体间的遗传距离明显大于群体内的遗传距离。AMOVA分析表明,斑鳜6群体间的总遗传分化指数Fst=0.7850(p<0.01),群体间遗传分化极显著。聚类分析表明:斑鳜不同群体内的所有个体均单独聚群,6个地理群体明显分为南北两大群,鸭绿江群体和海河群体聚为一支,长江、钱塘江、闽江和西江四个群体聚为另一支。斑鳜较高水平的遗传变异与其地理分布范围广,在不同的生态环境下积累了大量突变有关。不同地理群体间已产生了明显的遗传分化,其遗传亲缘关系与其地理分布格局基本一致,推测横亘于我国内陆中部地区、呈东西走向的秦岭山脉的形成可能是东亚斑鳜最先出现南北间群体分化的主要原因。

Siniperca scherzeri Steindachner,a high-valued freshwater fish,is endemic in East Asia. However,its natural resource has declined by the destruction on its ecological environment and excessive capture in fisheries. To investigate and understand ,its overall genetic background, genetic characteristics and divergences of Siniperca scherzeri Steindachner from Yalujiang River, Haihe River, Yangtze River, Qiantangjiang River, Minjiang River and Xijiang River were analyzed by AFLP methods. Eight primer pairs were selected from 64 EcoR I/Mse I primer combinations and used for further practical AFLP analysis. Total 211 bands were scored in 65 individuals with 126 polymorphic bands （59.7%） , some population specific bands were also observed. The genetic variation of Yangtze population was the highest （6.7%） among 6 populations, and genetic distances of inter-population were higher than that of intra-population. The analysis of molecular variance （AMOVA） showed that there was significantly genetic differentiation among 6 populations （p 〈 0.01 ）. NJ analysis showed that each population formed one group independently, the 6 geographic populations could be obviously grouped into two distinct clades. Yalujiang and Haihe populations are clustered in one clade, Yangtze, Qiantangjiang, Minjiang and Xijiang populations are clustered in another elade. The abundance of genetic variance of S. scherzeri in China maybe resulted from accumulation of a large numbers of mutations under wide distribution ranges in different ecosystems. Genetic divergence among 6 geographical populations are significant,moreover,the genetic relationships are consistent with their geographical distribution. The formation of Qinling Mountains,which lies across the central China from west to east,was invoked to explain the distinct divergence between the northern group and the southern group.