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 Cultured Populations of Larimichthys crocea

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)和宁德养殖群体(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=0.757 6-0.877 5、π=0.002 6-0.003 1)明显高于2个养殖群体(h=0.194 7-0.495 2、π=0.000 8-0.001 0),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(F_(st)=0.128 5、0.086 0,P<0.05),NDYZ与3个野生群体间具有遗传同质性(F_(st)=-0.010 6-0.000 2,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。

In order to clarify the genetic variation characteristics of wild and cultured populations of Larimichthys crocea,the genetic diversity,haplotype distribution,genetic differentiation and historical dynamics of five L.crocea populations,including Xuwen East Coast wild population(XWD),Naozhou Island wild population(NZD),Minyue East wild population(MYD),Xiangshan cultured population(XSYZ)and Ningde cultured population(NDYZ),were compared and analyzed by using COI gene sequence.The results showed that the genetic diversity level of the three wild populations(h=0.7576-0.8775,π=0.0026-0.0031)was significantly higher than that of the two cultured populations(h=0.1947-0.4952,π=0.0008-0.0010),and the haplotype distribution frequency of the two groups was significantly different.There was a significant genetic differentiation between XSYZ and NDYZ,MYD populations(F st=0.1285,0.0860,P<0.05).There was genetic homogeneity between NDYZ and three wild populations(F st=-0.0106-0.0002,P>0.05).The historical dynamic analysis supported the late Pleistocene population expansion of wild L.crocea,but did not support the population expansion of cultured L.crocea.Studies have shown that the differences in genetic diversity among populations reflect the mechanism of different evolutionary forces in the genetics of wild and cultured populations of L.crocea.Breeding practices and artificial selection have played an important role in the genetic differentiation of L.crocea populations in the East China Sea,while some factors,such as population expansion,breeding escape,artificial release and species diffusion ability may promote the genetic homogeneity between L.crocea populations in the western Guangdong sea area and the East China Sea.This study revealed the status of germplasm resources of L.crocea populations in the coastal waters of the western Guangdong and East China Sea and the differences in genetic characteristics between wild and cultured populations,which could provide scientific basis for the protection and utilization of germplasm resources of L.crocea.