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.