基于线粒体cytb序列的花斑蛇鲻种群遗传结构研究

Population genetic structure of brushtooth lizardfish(Saurida undosquamis) based on mitochondrial cytochrome b gene sequences

文章利用线粒体细胞色素b(cytochrome b,cytb)基因全序列作为分子标记,分析了中国近海和陆架的花斑蛇鲻(Saurida undosquamis)的遗传结构特征。从8个采样点266尾样本中共检测到142种单倍型,各采样点均表现出很高的单倍型多样性(0.9251~0.9929)和较低的核苷酸多样性(0.003145~0.003852)。单倍型的中间连接网络图呈现以4个优势共享单倍型为中心的星状发散结构,未发现与地理群体对应的谱系结构。分子方差分析表明花斑蛇鲻的遗传变异绝大部分(99.79%)来自种群内的个体之间,而群体之间几乎没有贡献遗传变异。成对遗传分化系数(FST)显示花斑蛇鲻群体间基因交流频繁,不存在明显的遗传差异,是一个随机交配群。中性检验表明种群历史动态显著偏离稳定种群模型,核苷酸错配分布表明花斑蛇鲻历史上曾经历过种群的快速扩张,扩张时间推算约在距今4万~10万年之前。研究结果表明,中国近海和陆架的花斑蛇鲻遗传分化不显著,在渔业上可以作为一个单元来管理。

We examined the population genetic structure of brushtooth lizardfish(Saurida undosquamis)from the coastal waters and continental shelf of China based on the complete cytochrome b gene sequences.A total of 142 haplotypes have been derived from 266 individuals at eight sampling sites.Genetic diversity analysis shows that the S.undosquamis samples were characterized by rather high haplotype diversity(0.9251-0.9929)and relatively low nucleotide diversity(0.003145-0.003852).Median joining network shows that the haplotypes were connected in a star-like manner with four dominant haplotypes without clades of samples corresponding to sampling localities.Analyses of molecular variance suggest that nearly all the genetic variation(99.79%)was from individuals within population rather than from the populations.The pairwise FST reveals no genetic differentiation among different populations.A high rate of gene flow between populations implies a panmixia for S.undosquamis among the sampling sites.Neutrality tests show significant deviation of population historical dynamics from stable population model,and mismatch distribution analysis indicates a late Pleistocene expansion in S.undosquamis.The expansion time was estimated to be 40-100 thousands years ago.The results reveal that S.undosquamis from the coastal waters and continental shelf of China belong to the same population and can be managed as a unit in fisheries.