大黄鱼野生和养殖群体的COI序列变异分析

Analysis of COI Sequence Variation in the Wild and Farmed Populations of Larimichthys crocea

关键词:  大黄鱼  COI基因  序列变异  遗传分化  种质资源

Key words:  Larimichthys crocea  COI gene  sequence variation  genetic differentiation  germplasm resource

摘要:

为阐明大黄鱼Larimichthys crocea野生和养殖群体的遗传变异特性，本研究采用COI基因序列对徐闻东岸野生群体（XWD）、硇洲岛野生群体（NZD）、闽粤东野生群体（MYD）、象山养殖群体（XSYZ）、宁德养殖群体（NDYZ）等5个大黄鱼群体的遗传多样性水平、单倍型分布、遗传分化、历史动态等进行比较分析。结果显示，3个野生群体的遗传多样性水平（h=0.7576 - 0.8775、π=0.0026 - 0.0031）明显高于2个养殖群体（h=0.1947 - 0.4952、π=0.0008 - 0.0010），二者的单倍型分布频率差异明显；XSYZ与NDYZ、MYD群体间存在显著的遗传分化（Fst=0.1285、0.0860，P<0.05），NDYZ与3个野生群体间具有遗传同质性（Fst=-0.0106 - 0.0002，P>0.05）。历史动态分析支持野生大黄鱼经历了晚更新世的群体数量扩张，但不支持养殖大黄鱼发生群体扩张。研究表明群体间遗传多样性的差异反映了不同进化力量在大黄鱼野生和养殖群体遗传中的作用机制。养殖实践和人工选育对东海区大黄鱼群体间的遗传分化起到了重要作用，而群体扩张、养殖逃逸、人工放流以及物种的扩散能力等因素可能促使粤西海域和东海区大黄鱼群体间具有遗传同质性。本研究揭示了粤西海域和东海区大黄鱼群体种质资源状况以及野生群体与养殖群体间的遗传特性差异，可为大黄鱼种质资源保护和利用提供科学依据。

Abstract:

To elucidate the genetic variation characteristics of Larimichthys crocea in the wild and farmed populations, the mitochondrial COI gene sequence was used to compare and analyze the genetic diversity level, haplotype distribution, genetic differentiation, and demographic history of five populations in this study, including the east coast of Xuwen wild population (XWD), Naozhou Island wild population (NZD), Min-Yuedong wild population (MYD), Xiangshan farmed population (XSYZ), and Ningde farmed population (NDYZ). The results showed that genetic diversities of three wild populations (h = 0.7576 - 0.8775, π= 0.0026 - 0.0031) were significantly higher than that of two farmed populations (h = 0.1947 - 0.4952, π= 0.0008 - 0.0010). The distribution frequency of haplotypes was also significantly different between wild and farmed populations. There were significant genetic differences between XSYZ and NDYZ, MYD populations (Fst=0.1285 and 0.0860, P<0.05), while the genetic homogeneity was detected between NDYZ and three wild populations (Fst=-0.0106 - 0.0002, P>0.05). Demographic history analysis revealed the growth of wild L.crocea in the effective population size during the late Pleistocene, but didn’t support the population expansion in the farmed L.crocea. The difference of genetic diversity among populations reflects the action mechanism of different evolutionary forces in the genetics of wild and farmed L.crocea. It can be concluded that aquaculture practices and artificial breeding play an important role in genetic differentiation among L.crocea populations in the East China Sea. Some factors, such as population expansion, breeding escape, artificial release, and species dispersal ability, may promote genetic homogeneity between L.crocea populations in western Guangdong and the East China Sea. This study revealed the status of germplasm resources and the differences of genetic property between wild and farmed populations of L.crocea distributed in the coastal waters of the western Guangdong and East China Sea, providing scientific basis for the protection and utilization of L.crocea germplasm resource.