河蚬微卫星引物筛选及洪泽湖野生群体遗传结构分析

摘要

利用磁珠富集法筛选了河蚬10对中高度多态性的微卫星引物,并分析了洪泽湖河蚬4个野生群体的遗传结构.结果表明,每个群体至少有4个位点经Bonferroni校正后显示杂合不足,显著偏离了Hardy -Weinberg平衡(P＜0.013)；4个群体平均期望杂合度均大于0.752,显示出较高的遗传多样性水平,蒋坝、临淮群体遗传多样性高于高良涧和老子山群体；突变-漂移平衡分析结果显示,4个群体在IAM模型下偏离了突变-漂移平衡,高良涧群体在TPM模型下偏离了突变-漂移平衡,且表现杂合过剩,说明少数群体即将或曾经经历瓶颈效应,群体数量已出现波动；群体间AMOVA分析表明,洪泽湖河蚬群体间遗传分化程度较低(FST=0.017 7＜0.05),仅有1.77％的变异来自群体间,并没有形成显著的遗传结构,在种质资源保护和管理上可视作一个单元,这为河蚬种质资源保护和合理开发利用提供了理论指导.%Asian clam( Corbicula fluminea) is a commercially important freshwater bivalve in South and East Asia. However,food clam mainly comes from the wild resources,and the natural populations have declined greatly and rapidly due to overfishing and natural habitats degradation. In China, the germplasm resource protection zone of C. Fluminea has been set up in Hongze Lake to protect the natural resources. In this paper, genetic structure of four wild C. Fluminea populations in Hongze Lake was analysized using ten polymorphic microsatellite DNA loci isolated and characterized by magnetic beads enrichment methods. The results showed that at least four of the loci were observed to have significant heterozygosity deficiency and obvious deviations from Hardy-Weinberg equilibrium(P<0.013) after Bonferroni correction in the four populations. Although values of expected heterozygosity were all above 0.752 and displayed high genetic diversity in the four populations,the level of genetic diversity fluctuated obviously. For example,the genetic diversity of the Jiangba and Linhuai populations was higher than that of the Gaoliangjian and Laozishan populations. The departure from mutation-drift equilibrium with partly heterozygote excesses was detected in all the C. Fluminea populations under the IAM models and in Gaoliangjian population under the TPM models using Bottleneck software, which might indicate that the population structure has suffered bottleneck effects in the past, or was about to experience bottleneck effects, as well as the recent population fluctuation. AMOVA analysis across all populations and loci showed that there were the low levels of genetic divergences among the four populations ( FST =0. 017 7 <0. 05). 1. 77% of genetic variation was attributed to among populations. It suggested that all C. Fluminea populations in Hongze Lake could be protected and managed as a single unit in genetic resource. All the study results would offer theoretical direction for the protection and utilization of the C. Fluminea germplasm in Hongze Lake.