军曹鱼群体遗传结构的AFLP分析

摘要

筛选出10对扩增片段长度多态分析技术(Amplified fragment length polymorphism,AFLP)的选择性扩增引物(E-aga/M-cgt、E-aga/M-cga、E-agc/M-cga、E-agg/M-cga、E-act/M-cgc、E-aag/M-cgc、E-aca/M-cga、E-aac/M-cgc、E-aac/M-cac和E-aac/M-cat),分析了4个军曹鱼(Rachycentron canadum)全人工繁育群体海南1(HN1)、海南2(HN2)、湛江(ZJ)和流沙湾(LS)的遗传结构.结果表明:总体多态位点比例(83.9%)、分化指数(0.4278)和Shannon信息指数(0.6149)均处于较高水平,遗传多样性丰富;主坐标分析和邻位连接树中LS-HN2支与ZJ-HN1支明显分离,各群体内多样性水平存在差异(遗传多样性大小依次为HN1、HN2、LS、ZJ),但总体基因流仍然较大(Nm＝10.327),分子方差分析(AMOVA)获得的群内方差(53%)也略大于群间(47%).%Ten primer pairs of AFLP, E-aga/M-cgt, E-aga/M-cga, E-agc/M-cga, E-agg/M-cga, E-act/M-cgc,E-aag/M-cgc, E-aca/M-cga, E-aac/M-cgc, E-aac/M-cac and E-aac/M-cat, were selected to determinegenetic structure of 4 cultured cobia (Rachycentron canadum) populations (Hainan1, Hainan2, Liushawanand Zhanjiang, and 30 individuals for each) based on 0/1 mat rix of 500 loci. Total percentage ofpolymorphic loci (83.9％), Nei's (1973) gene diversity (0.4278) and Shannon diversity index (0.6149)showed high values and genetic diversity. Differences between LS-HN2 and ZJ-HN1 were evident,evaluated by Principal Coordinates Analysis and Neighbor-Joining (NJ) tree of Nei's genetic distance.However, estimate of gene flow (Nm) from Gst was 10.327 and analysis of molecular variance showedthat the variance within the population (53％) was slightly greater than that among populations（47％）.