中国沿海拟穴青蟹群体遗传多样性的微卫星分析

Microsatellite analysis on genetic diversity of seven wild populations of Scylla paramamosain in China

利用17对微卫星引物对我国沿海7个拟穴青蟹野生群体(杭州湾、三门湾、闽江口、东山湾、珠江口、北部湾、清澜港)进行了遗传多样性分析。结果表明,17个位点在所有青蟹群体中均为高度多态(PIC>0.5),共检测到253个等位基因;7群体的平均等位基因数(A)为9.41～10.94,平均有效等位基因数(Ne)为5.42～6.87,平均杂合度(H)为0.511～0.563,群体遗传多样性水平较高。分子方差分析(AMOVA)结果显示,94.13%的遗传变异存在于群体内,5.87%的遗传变异存在于群体间,两两群体间FST值为0.035 5～0.081 7(P<0.01),表明群体间遗传分化水平中等偏低。Hardy-Weinberg平衡检测表明,7群体普遍存在杂合子缺失现象。青蟹群体间遗传距离为0.253 0～0.571 9,UPGMA聚类分析表明,杭州湾与三门湾群体首先聚在一起,再与闽江口群体、东山湾群体聚为一支;珠江口群体与清澜港群体聚为另一支;两分支最后与北部湾群体聚类在一起。

The genetic diversity of seven wild Scylla paramamosain populations,collected from Hangzhou Bay（HZ）,Sanmen Bay（SM）,Minjiang Estuary（MJ）,Dongshan Bay（DS）,Zhujiang Estuary（GD）,Beibu Bay（GX）,Qinglan Estuary（HN）in China were investigated using seventeen microsatellite markers.The number of alleles（A）,number of effective alleles（Ne）,polymorphism information content（PIC）and heterozygosity（H）were all determined.The Hardy-Weinberg Equilibrium was checked by χ2 Test.The genetic distance was computed based on the allele frequency.A dendrogram was built on the unweighted pair-group method with arithmetic means（UPGMA）results using PHYLIP software package（Ver 3.5）.F-statistics analysis and the degree of population differentiation between the seven wild populations using analysis of molecular variance model（AMOVA） were computed by ARLEQUIN（Ver 3.1）.A total of 253 alleles were obtained at the seventeen microsatellite markers in seven populations.Polymorphic information content（PIC） value per locus was greater than 0.5,indicating the seventeen loci were highly polymorphic.The mean number of alleles and effective alleles ranged from 9.41 to 10.94,5.42 to 6.87 respectively.The heterozygosity（H） ranged from 0.511 to 0.563.The data suggested that all the seven wild populations of Scylla paramamosain had little high genetic diversities.Analysis of molecular variance（AMOVA） revealed that the variation within populations was 94.13%,whereas the variation among populations explained 5.87% of the total variation.F-statistics analysis detected significant genetic differentiation among the seven wild populations,with the FST value ranged from 0.035 5 to 0.081 7.Genetic differentiation among populations was statistically significant.88.24% of the population loci showed significant deviation from the Hardy-Weinberg equilibrium.There was heterozygote deficiency at all loci.The genetic distances among populations ranged from 0.253 0 to 0.571 9.Cluster analysis indicated that HZ and SM populations,joining together for the closest relationship,were clustered with MJ and DS as one cluster.GD and HN populations were clustered together,while GX was an independent cluster.