东太平洋公海茎柔鱼种群遗传结构初步研究

Primary studies on the population genetic structure of Dosidicus gigas in the high seas of eastern Pacific Ocean

根据2009年7月到10月我国大型鱿钓渔船在东太平洋(81.9°～94.9°W,8.9°N～11.3°S)秘鲁和哥斯达黎加外海作业期间采集的样本,利用线粒体DNA细胞色素b基因的724 bp部分序列,分析了采自秘鲁7个采样点和哥斯达黎加3个采样点的155个个体的序列多样性与种群遗传结构。结果显示,724 bp片段中发现了16个变异位点,155个个体出现43个单倍型。序列多样性分析结果揭示,155个个体的平均单倍型多样性指数为0.873,核苷酸多样性指数为0.003 69。群体间共享6个单倍型,秘鲁外海茎柔鱼群体享有最多特有单倍型(20个)。分子方差分析揭示,82.70%的遗传变异性出现在种群内;群体间的FST分析揭示部分秘鲁群体与哥斯达黎加群体,部分秘鲁群体间存在着显著的遗传分化;而哥斯达黎加群体内部不存在显著的遗传分化。

The jumbo flying squid（Dosidicus gigas）is commercially important fishery species in the world.Assessment of population genetic diversity levels of jumbo flying squid is fundamental to the conservation and management of this species.The samples derived from the Chinese squid jigging vessel were collected from the eastern Pacific waters（81.9°-94.9°W,8.9°N-11.3°S）from July to October 2009.By using 724 bp fragment of mitochondrial cytochrome b gene（Cyt b）,we analyzed the sequence variations and population genetic structures for 155 samples collected from seven sites of Peru and three sites of Costa Rica.In total,16 variable sites were acquired,and all of them were parsimony sites.43 haplotypes were identified from 155 individuals.Analysis of mtDNA Cyt b sequences of jumbo flying squids from the ten localities revealed that the mean haplotypic diversity was 0.873,while the nucleotide diversity was 0.003 69.6 haplotypes were shared by all the populations,while Peru population possessed the highest haplotypes（n=20）.The AMOVA test of D.gigas revealed that 82.70% of the genetic variation occurred within populations.FST analysis suggested that significant genetic differentiations were found between the partial Peru populations and the Costa Rica populations,and even between partial Peru populations.However,no significant genetic differentiations were detected between Costa Rica populations.