基于线粒体控制区序列的南海圆舵鲣种群遗传结构分析

Analysis of population genetic structure of bullet tuna(Auxis rochei) in the South China Sea based on mitochondrial control region sequences

利用线粒体控制区(D-loop)高变区序列作为遗传标记,分析了中国南海5°N^21°N之间7个圆舵鲣(Auxis rochei)地理群体的遗传结构特征。201尾样本的D-loop区序列共检测到185种单倍型。各个采样点均呈现出很高的单倍型多样性(0.958 2~1.000 0)和较高的核苷酸多样性(0.034 327~0.041 235)的特征。单倍型邻接关系树未呈现与地理群体对应的谱系结构。分子方差分析和成对遗传分化系数(FST)显示南海海域圆舵鲣的遗传变异主要来自群体内(98.33%),群体间基因交流频繁,是一个随机交配群。核苷酸不配对分布和中性检验表明南海圆舵鲣在更新世晚期曾经历过种群的快速扩张。结果表明,南海圆舵鲣具有丰富的遗传多样性水平,遗传分化不显著,在渔业上可以作为一个单元来管理。

Based on hypervariable region of mitochondrial control region（ D-loop） sequences,we examined the population genetic structure of the bullet tuna（ Auxis rochei） collected from seven locations between 5°N to 21°N in the South China Sea. A total of 185 haplotypes were defined from 201 individuals of fishes. The genetic diversity analysis shows that the samples of A. rochei from the seven locations in the South China Sea possessed quite high haplotype diversity（ 0. 958 2 - 1. 000 0） and high nucleotide diversity（ 0. 034 327 - 0. 041 235）. The neighbor-joining tree for D-loop haplotypes reveals no significant genealogical clades of the fish samples corresponding to the sampling locations. Analyses of molecular variance and pairwise FSTsuggest most of the genetic variation（ 98. 33%） was attributed to variability within populations. A high rate of gene flow between different populations implies a panmixia for A. rochei in the South China Sea. Both mismatch distribution analysis and neutrality tests indicate a late Pleistocene expansion in A. rochei. The results demonstrate that A. rochei in the South China Sea belong to the same population with high genetic diversity.Thus,a single-stock management regime can be supported in fishery management.