长江草鱼不同群体EST-SSR 多态性标记的筛选及其遗传结构分析

为对我国不同地域草鱼群体进行鉴定和遗传多样性分析, 在2400 条草鱼EST 序列中, 对其二碱基至五碱基重复序列进行筛选, 共筛选出微卫星位点181 个, 选取其中的46 个进行引物的设计与合成, 获得呈多态性的微卫星引物9 对。利用这9 对引物对8 个长江水系草鱼群体和1 个红色草鱼自然突变群体进行了遗传结构分析。结果显示, 长沙草鱼、安庆草鱼、嘉兴草鱼、靖江草鱼、石首草鱼、松江草鱼、瑞昌草鱼、邗江草鱼和红色突变草鱼9 个群体的平均等位基因数(Na)分别为4.67、5.22、5.33、5.00、4.89、4.78、4.89、4.67 和2.56, 平均期望杂合度(He)分别为0.6397、0.6543、0.6831、06356、0.6737、0.6483、0.6664、0.7129 和0.4696, 平均多态信息含量(PIC)分别为0.5787、0.6126、0.6283、0.5894、0.6217、0.5956、0.6136、0.6582 和0.3949, 表明邗江草鱼的遗传多样性最高, 而红草鱼的遗传多样性最低。聚类分析表明, 8 个长江水系草鱼群体首先聚类, 最后与红色草鱼聚类;其中, 安庆草鱼与松江草鱼首先聚为一支, 遗传距离较近, 为0.0725;红色草鱼与长沙草鱼的遗传距离最远, 为0.5217。研究结果对我国草鱼种质资源保存、种群鉴定和良种选育具有重要意义。  

DETECTION OF EST-SSRS MARKERS AND GENETIC STRUCTURE OF DIFFERENT POPULATIONS OF GRASS CARP IN YANGTZE RIVER SYSTEM

In this study, we selected 181 microsatellite loci from 2400 EST sequences to perform germplasm identification and genetic diversity analysis in different regions of grass carp, Ctenopharyngodon idella. Nine pairs of primers, which could give stable and polymorphic amplification profiles, were screened out from 46 microsatellite loci and used to analyze the genetic structure of C. idella. The 9 pairs of primers were used to analyze the genetic structure of 8 populations of the Yangtze River (CSC, AQC, JXC, JJC, SSC, SJC, RCC and HJC) and 1 red population (HC). The mean value of number on alleles (Na) of CSC, AQC, JXC, JJC, SSC, SJC, RCC, HJC and HC was 4.67, 5.22, 5.33, 5.00, 4.89, 4.78, 4.89, 4.67 and 2.56, respectively. The mean value of expected heterozygosity (He) was 0.6397, 0.6543, 0.6831, 0.6356, 0.6737, 0.6483, 0.6664, 0.7129 and 0.4696, respectively. And the average value of polymorphism information content (PIC) was 0.5787, 0.6126, 0.6283, 0.5894, 0.6217, 0.5956, 0.6136, 0.6582 and 0.3949, respectively. It demonstrated that the genetic diversity of HJC was the highest and HC was the lowest among the nine populations. Using unweighted pair-group method with arithmetic means method (UPGMA) based on their genetic distances, the cluster analysis in nine populations showed that 8 populations of the Yangtze River first grouped together, then they clustered with the red population. In addition, the genetic distance between AQC and SJC was 0.0725, which was the nearest, the genetic distance between HC and CSC was 0.5217, which was the farthest. Our results will have important value in germplasm resources preservation, germplasm identification and breeding of C. idella.