基于线粒体COⅠ序列的泥螺群体遗传多样性研究

摘要

The mitochondrial DNA COⅠsequences were detected in snail Bullacta exarata from seven populations in Liaoning, Shandong, Jiangsu and Zhejiang provinces insight on genetic diversity and population structure to understand mechanism of the genetic diversity and to protect snail germplasm resources.The analysis of 145 pieces of fragments with the length of 631 bp revealed that the average contents of A, G, T, C, and A + T were 23.83%, 18.93%, 41.60%, 15.64%, and 65.43%, respectively and AT level higher than the GC content.The number of haploid genotype was 47 sharing type haploid number of 12.AMOVA analysis showed that the total genetic differentiation coefficient of COⅠ (Fst) from seven groups was 0.7893 (P<0.001), the genetic differentiation among populations was greater than that within population.The phylogenetic evolution tree constructed by NJ showed that individuals from seven geographic populations stayed together with each other and the same group had no obvious independent aggregation.Molecular variance analysis manifested that obvious genetic differentiation appeared between groups.%为初步研究泥螺的遗传多样性和群体结构,探讨其遗传多样性的产生背景和维持机制,便于今后更好地保护泥螺种质资源,本研究对辽宁、山东、江苏、浙江四省7个泥螺群体的线粒体细胞色素氧化酶亚基Ⅰ(COⅠ)部分序列进行了测定与分析,经过处理得到145条631 bp长度的核苷酸片段,分析显示A、G、T、C、A+T的平均含量分别为23.83%、18.93%、41.60%、15.64%、65.43%,AT 含量高于 GC 含量.单倍型总数47,共享单倍型数目12.用Arlequin 3.5 软件进行AMOVA 分析,表明7个群体间 COⅠ总遗传分化系数为0.7893(P<0.001), 群体间遗传分化大于群体内遗传分化.用邻接法构建的系统发育进化树显示,7个地理群体的泥螺互相聚在一起,同一群体之间没有明显独立聚在一起的情况.分子方差分析表明群体间出现明显的遗传分化.