利用微卫星标记比较分析拟穴青蟹不同家系的遗传多样性

Genetic diversity among different families of mud crab Scylla paramamosain by microsatellite markers

拟穴青蟹（Scylla paramamosain）是我国重要的海水养殖蟹类,随着市场需求量的增加及养殖规模的不断扩大,有必要培育高产、抗逆的优质新品种。家系选育是选择育种的有效途径,目前已应用于拟穴青蟹人工育种工作中。本研究利用8个微卫星标记对拟穴青蟹6个家系共275 ind个体进行了遗传多样性分析,共检测到50个等位基因,平均每个位点4-8个,其中3个家系各自在1个位点表现为单态,8个位点的PIC、HO和HE分别在0.40-0.77、0.33-0.81和0.42-0.80之间。对6个家系的分子方差分析（AMOVA）结果显示,家系间的固定系数FST=0.205 7,即总的遗传变异中有20.57%的变异来自家系间,79.43%的变异来自家系内。根据遗传距离采用UPGMA法对6个家系进行聚类分析,4号家系和5号家系之间的遗传距离最小,先聚合在一起,2号家系和6号家系间的遗传距离最大。本研究将为拟穴青蟹家系选择育种提供一定的理论依据。

The mud crab Scylla paramamosain is an important marine aquaculture crab in China.With the increase of market demands and aquaculture scale,it is important to develop a new variety with high yield and stress resistance.Family selection is an effective way for artificial breeding and has been used in S.paramamosain.Eight microsatellite markers were chosen for genetic analysis of 6 families,including 275 individuals of S.paramamosain.Results showed that 50 alleles were detected and PIC,HO and HE were 0.40-0.77,0.33-0.81 and 0.42-0.80,respectively.Analysis of molecular variance（AMOVA） showed that the fixation index（FST） was 0.205 7,suggesting 20.57% of genetic variation being from families,while 79.43% of genetic variation being within families.Nei＇s genetic distance was used to construct the dendrogram by using the unweighted pair group method with arithmetic mean（UPGMA） and results showed that family 4 and 5 had the shortest distance while family 2 and 6 had the longest distance.The study will be useful for artificial selective breeding of S.paramamosain.