长江草鱼多态微卫星位点的分离及后备亲鱼的遗传多样性分析

本研究采用磁珠富集法分离了10对具有多态性的草鱼(Ctenopharyngodon idellus)微卫星位点,并对140条长江野生草鱼组成的后备亲鱼群体的遗传结构进行了分析。结果显示:本试验得到的草鱼微卫星序列主要是以2个碱基为重复单位、重复次数在5～22之间的多重复单元,重复次数在10次以上的微卫星序列较易得到多态性;77个微卫星座位中,完美型、非完美型和混合型微卫星标记所占的比例分别为87.01%、2.60%和10.39%;群体遗传分析显示,10个多态性微卫星座位中,除了GC39座位外,其它座位都符合哈迪-温伯格平衡,适用于草鱼群体的遗传结构分析;每个座位检测到3～8个等位基因,平均有效等位基因数为3.9302,多态信息含量在0.4129～0.8107之间变动,平均为0.6678,除了GC78座位为中度多态外,其他9个座位均为高度多态。基因分化系数、Shannon指数、平均观测杂合度和平均期望杂合度的平均值分别为0.3457、1.4262、0.9511和0.7193,表明该群体的遗传多样性比较丰富。

Microsatellite markers isolation and genetic analysis of wild grass carp(Ctenopharyngodon idellus) in Yangtze River

Ten new pairs of microsatellite primers with high amplified polymorphisms were isolated from grass carp(Ctenopharyngodon idella) genome with magnetic beads,and were used to analyse the genetics of Yangtze River wild grass carp population composed of 140 individuals.The results showed that in the analyzed microsatellite sequences,dinucleotide repeats were the most frequent type,and the repeat number is between 5 and 22.In addition,the microsatellite sequences with repeat number more than 10 were easily detected to be polymorphic in the grass carp population.Among the 77 microsatellites,67 were perfect(87.01%),2 were imperfect(2.60%) and 8 were compound type(10.39%).The genetic analysis of the wild population showed that among the ten polymorphic microsatellite loci,only GC39 deviated significantly from Hardy-Weinberg equilibrium,others were all suitable to the genetic analysis of grass carp population.3 to 8 alleles were detected at each locus and the average number of effective alleles was 3.9302.The polymorphism information content(PIC) value ranged from 0.4129~0.8107 and only GC78 was middle-polymorphism locus,others were all high-polymorphism loci.Average of inbreeding coefficient(Fst),Shannon′s information index(I),observed heterozygosity(Ho) and expected heterozygosity(He) observed heterozygosity(Ho) in the wild population was 0.3457,1.4262,0.9511 and 0.7193 respectively,which indicated that this population had high genetic diversity.