秦皇岛近海增殖放流区牙鲆(Paralichthys olivaceus)回捕群体的遗传多样性分析

本研究利用12对微卫星标记对秦皇岛近海增殖放流区内的牙鲆(Paralichthys olivaceus)回捕群体的遗传多样性进行分析，并与放流用牙鲆亲本群体和放流前群体的遗传多样性进行对比。结果显示，在3个群体中，等位基因数(Na)为11.917–22.167个，平均观测杂合度(Ho)为0.800–0.836，平均期望杂合度(He)为0.814–0.845，平均多态信息含量(PIC)为0.775–0.818。其中，回捕群体的平均Na最多，为22.167，放流前群体的平均Na最少，为11.917。平均Ho最大的是回捕群体(0.836)，最小的是放流前群体(0.800)。平均He最大的是亲本群体(0.845)，最小的是放流前群体(0.814)。在36个群体–位点组合中，有23个群体–位点组合显著偏离哈迪-温伯格平衡状态(P<0.05)。3个群体的基因分化系数Gst值为0.005–0.043，遗传分化均为较弱。研究表明，3个群体均保持较高的遗传多样性，放流人工培育苗种对回捕群体的遗传多样性和遗传结构未产生明显的影响。

Analysis of the Genetic Variability of the Captured Population of Japanese Flounder Paralichthys olivaceus in the Coastal Releasing Area of Qinhuangdao

Japanese flounder Paralichthys olivaceus is the major species of released fish in the coastal area of Qinhuangdao. In recent years, the ecological and genetic risks caused by releasing a large number of hatchery-reared fish to the sea have attracted more and more attention. In this study, we used 12 microsatellite markers to analyze the genetic variability of the captured population of P. olivaceus from the coastal releasing area of Qinhuangdao. We also compared parameters of genetic diversity among the brood stock, the pre-releasing population and the captured population. The mean number of alleles was between 11.917 and 22.167, and the maximum and minimum values were found in the captured population and the pre-releasing population respectively. The mean observed heterozygosity (Ho) ranged from 0.800 to 0.836, and the mean expected heterozygosity (He) was between 0.814 and 0.845. The brood stock had the highest He value, and the pre-releasing population had the lowest value. The mean polymorphism information content (PIC) ranged from 0.775 to 0.818. Twenty-three out of 36 group-loci combinations were significantly deviated from the Hardy-Weinberg equilibrium (P<0.05). The Gst values among the five populations varied from 0.005 to 0.043, indicating a low level of differentiation. Results of this study suggested the high genetic diversity of these three populations. Moreover, no obvious genetic risk was caused by the large-scale releasing of hatchery-reared fish in the coastal releasing area of Qinhuangdao.