基于线粒体D-loop基因的中国海三疣梭子蟹遗传多样性与遗传分化研究

为探明分布于中国四大海区的天然三疣梭子蟹群体遗传多样性与遗传分化状况,实验以大连(DL)、东营(DY)、连云港(LYG)、舟山(ZS)、湛江(ZJ)和漳州(ZZ)6个三疣梭子蟹地理群体为研究对象,采用线粒体控制区D-loop全基因序列为分子标记,对中国海三疣梭子蟹野生群体的遗传多样性及群体遗传结构进行了分析。结果发现,在用于分析的1 141 bp的D-loop全基因序列中共有185个变异位点,129个简约信息位点。60个个体中共计48个单倍型,单倍性多样性指数和核苷酸多样性指数显示中国沿海三疣梭子蟹群体具有较高的遗传多样性,而且三疣梭子蟹在过去没有出现很强的选择效应,群体大小稳定。6群体三疣梭子蟹遗传分化指数(F_ST)为0.189 7,将中国沿海三疣梭子蟹作为一个大群体来讲已产生了中度分化,群体分化时间推断为(19.68～26.05)万年。LYG分别和DY、ZJ、ZZ,以及ZJ和ZZ这4组之间无明显分化,基因流较大(N_em>5),而其他11个群组间已存在一定程度的分化。特别是ZS与其它5群体产生了高度的遗传分化,DL与其他4群体发生了中度分化。遗传距离与地理距离不存在显著的相关性,群体发生与扩散可能有更复杂的原因。

Genetic diversity and genetic differentiation of swimming crab (Portunus trituberculatus)from six geographical populations of China Sea based on mitochondrial D-loop gene

A swimming crab is one of the most economically important edible marine crabs in the East Asia area,and it is widely distributed in the coastal waters of China,Japan and Korea.To assess the level of genetic diversity and genetic variation of swimming crab populations along China coasts,the species from the six geographical populations from China Sea(Dalian,Dongying,Lianyungang,Zhangzhou,Zhoushan and Zhanjiang)were studied based on mitochondrial D-loop whole gene sequences.There were 1 141 bp,185 variation sites and 129 parsimony informative sites in D-loop whole gene sequences.And there were 48 haplotypes among 60 swimming crab individuals.Nucleotide diversity index and Haplotype diverstity index together revealed a high genetic diversity and low selective effect for swimming crab populations in China Sea.The genetic differential index F_ST of total six populations was 0.189 72,which meant that the genetic differentiation among populations was moderate and significant(P<0.05)and the inferred differentiation time was about(196.8-260.5)×10³ years.Low gene flow indicated that there were genetic differentiations among the fifteen groups,except between LYG and DY,ZJ,ZZ,respectively,in addition between ZJ and ZZ(N_em>5).Especially,there were pronounced levels of genetic differentiation between ZS and the others and a moderate genetic differentiation between DL and LYG,DY,ZJ and ZZ,respectively.The genetic distance had no significant correlation with geographical distance,so there may be more intricate reasons in population occurrence and spread.