广西稻田养殖金边鲤群体遗传多样性分析

Genetic Structure Analysis of Local Variety of Common Carp Cyprinus carpio var. Jinbian Farmed in Paddy Fields in Guangxi Region

为了解广西稻田养殖金边鲤群体的遗传多样性现状,本研究利用10个高度多态微卫星标记,以野生太湖鲤和黑龙江鲤群体,池塘养殖福瑞鲤、兴国红鲤、建鲤群体,广西稻田养殖晒江鲤群体作对照,共7个鲤鱼群体进行群体遗传结构分析。试验结果显示,10个位点共检测到242个等位基因,每个群体的平均等位基因数、期望杂合度、观测杂合度和多态信息含量分别为6~16、0.736~0.900、0.620~0.800和0.689~0.878。9个位点在7个鲤鱼群体中的等位基因频率显著偏离哈迪—温伯格平衡(P<0.05),7个鲤鱼群体遗传多样性丰度由高到低顺序为太湖鲤、黑龙江鲤、建鲤、晒江鲤、福瑞鲤、金边鲤、兴国红鲤。所有群体的遗传分化系数值为0.015~0.141,表明7个鲤鱼群体间存在不同程度的遗传分化,其中金边鲤群体与野生和池塘养殖群体间遗传分化均达中等程度。AMOVA分析显示,群体间的遗传分化占7.15%,而群体内的遗传分化占92.85%,表明鲤鱼群体主要的遗传分化来自于群体内部。7个鲤鱼群体间的遗传距离为0.286~0.977,根据Nei′s遗传距离所绘制的聚类图显示,7个鲤鱼群体被划分为4大支,贝叶斯分析结果与聚类结果相似,其中两个稻田鲤群体遗传结构相似聚为一类。本研究是对金边鲤遗传背景的初探,试验结果表明,金边鲤群体具有较高的遗传多样性和进一步选育的潜力。本研究结果可为稻田养殖鲤品种的选育和遗传改良提供基础遗传学信息。

In this study,genetic diversity and population structure were investigated in 224 samples of 7 strains of common carp including two wild populations(Heilongjiang carp Cyprinus carpio haematoperus,Taihu carp),three pond cultured strains(FFRC strain of common carp C.carpio var.FFRC,Xingguo red carp C.carpio var.singuonensis,Jian carp C.carpio var.jian and two populations(Jinbian carp C.carpio var.Jinbian and Shaijiang carp C.carpio)farmed in rice field by 10 highly polymorphic microsatellite markers to comprehend the genetic information on the local variety of paddy field Jinbian carp in Guangxi.A total of 242 different alleles were detected,with mean number of alleles per population ranging from 6 to 16,mean expected heterozygosity from 0.736 to 0.900 and observed heterozygosity ranging from 0.620 to 0.800.The mean value of polymorphism information content was ranged from 0.689 to 0.878,and nine microsatellite loci were found to deviate significantly(P<0.05)from the Hardy-Weinberg equilibrium after Bonferroni correction in 7 populations.As a whole,the descending order of genetic diversity of 7 common carp populations was expressed as Taihu carp,Heilong river carp,Jian carp,Shaijiang carp,FFRC strain common carp,Jinbian carp and Xingguo red carp,with genetic differentiation coefficient varying from 0.015 to 0.141,indicating that the different degrees of genetic differentiation among the seven populations and the genetic differentiation between Jinbian carp population with the other else populations was medium except Shaijiang carp population.Global analysis of hierarchical gene diversity further revealed that the total genetic variation among populations was 7.15%,whilst variation within populations was estimated to be 92.85%,which showed that the majority of total microsatellite loci variation was appeared to be within populations.The genetic distance among the seven populations was ranged from 0.286 to 0.977,and the phylogenetic tree was constructed based on Nei′s standard genetic distance,and the UPGMA algorithm grouped the 7 populations into four major clusters.Bayesian analysis also indicated that these seven common carp populations were clustered into four groups,the two rice field breeding populations being divided into one of the clusters.These findings indicated that Jinbian carp variety paddy field carp population showed a high level of genetic diversity and had some potential for further selective breeding,which provides basic genetic information for breeding and genetic improvement of the new varieties of common carp in paddy fields.