基于线粒体控制区的中部太平洋黄鳍金枪鱼种群遗传结构的研究

Genetic population analysis of Thunnus albacares from central Pacific Ocean based on mitochondrial DNA control region

根据2010年9月-2012年1月,我国远洋捕捞船在太平洋中部(16°S^8°N;160°W^155°E)的7个采样点采集到的101个样本,利用线粒体DNA控制区(mtDNA D-loop)基因的585 bp序列,分析了它们的遗传多样性和遗传结构。结果显示,585 bp片段中发现23个变异位点,80个单倍型;序列多样性分析结果显示,7个采样群体单倍型多样性指数h=0.994±0.002和核苷酸多样性指数π=0.00892±0.00038。分子方差分析揭示98.18%的遗传变异来自种群内,群体间的Fst分析揭示黄鳍金枪鱼7个采样群体内部不存在显著的遗传分化。Fu’s Fs呈负值和核苷酸不配对呈单峰,显示了黄鳍金枪鱼大约在335~544万年前经历了种群扩张;基因交流与遗传分化分析表明,该7个采样点的黄鳍金枪鱼群体之间存在强烈的基因交流,种群遗传分化水平较低。黄鳍金枪鱼种群遗传多样性低,为单一种群,应采用合理的有效措施进行管理,确保黄鳍金枪鱼产业的可持续发展。

The samples derived from the Chinese vessels were collected from 7 locations of central Pacific Ocean waters（ 16° S- 8° N; 160° W- 155° E） from September 2011 to January 2012. By using 585 bp fragments of mtDNA control region,we analyzed the sequence variations and genetic structures of 101 samples collected from 7 locations. In total,23 variable sites were acquired,and 80 haplotypes were identified.Analysis of mtDNA D-Loop gene sequences from 7 localities revealed that the mean haplotypic diversity and nucleotide diversity was 0. 994 ± 0. 002 and 0. 00892 ± 0. 00038,respectively. The AMOVA tests revealed that 98. 18% of the genetic variation occurred within populations. Fstanalysis suggested that no significant genetic differentiations were found within the 7 localities. Neutrality test and the mismatch distribution indicated a recent population expansion that occurred about 3 350 000- 5 440 000 years ago,suggesting a frequency genetic exchange and a poor genetic structure. A single population and a low genetic diversity call for a responsible and effective management to ensure the sustainable development of yellowfin tuna.