漠斑牙鲆养殖群体微卫星遗传多样性的初步分析

Primary analysis on genetic diversity in cultured stocks of Southern flounder(Paralichthys lethostigma) using microsatellite DNA marker

为评估养殖过程对漠斑牙鲆遗传结构的影响,本研究利用微卫星标记对漠斑牙鲆(Paralichthys lethostigma)山东胶南养殖群体(子一代)和江苏南通养殖群体(子三代)的遗传结构进行分析比较,结果表明所使用的14对引物中,11对引物在所选取的群体中具有多态性,两个群体中共检测出了70个等位基因(42个有效等位基因),总群体的平均观察杂合度(Ho)和期望杂合度(He)分别为0.36和0.60。两个群体的Shannon’s遗传多样性指数分别为1.18和1.07,Nei’s遗传多样性指数分别为0.56和0.51,表明山东胶南群体的遗传多样性显著高于江苏南通养殖群体。两个养殖群体间的两群体间的遗传分化系数Fst平均为0.1246,遗传距离(Ds)为0.171,遗传相似度为0.8432,表明两个群体中度分化。由此可以得出,在中国随着漠斑牙鲆累代养殖的开展,其遗传多样性下降显著,遗传结构已经出现了显著分化。因此,在将来的繁育过程中应制定合理的育苗规划以维持漠斑牙鲆的多样性水平并保障产业可持续发展。

In this study, the genetic variation and genetic structure of the first filial generation （Jiaonan cultured stock） and the third filial generation （Nantong cultured stock） of Paralichthys lethostigma were investigated using microsatellite DNA techniques. Of the 14 microsatellite DNA markers, 11 loci were polymorphic. A total of 70 al-leles （42 effective alleles） were detected at the 11 loci in the total populations. The number of alleles per polymor-phic loci ranged from 2 to 14 with an average of 7.3, the average observed and expected heterozygosities of the 11 polymorphic loci were 0.36 and 0.6, respectively. The Shannon’s index of Jiaonan and Nantong populations was 1.18 and 1.07, and the Nei’s index of the two populations was 0.56 and 0.51, respectively. The results showed that the genetic diversity of the Jiaonan population was higher than that of the Nantong population. The genetic similar-ity coefficient and the genetic distance between the two populations was 0.8432 and 0.171, respectively. The value of the Fst （0.1246） indicated that the genetic differentiation between the two populations was moderate. It can be concluded that the genetic diversity of the southern flounder population degenerated dramatically and genetic structure had differentiated significantly after several generations of cultivation in China. Thus, the scientific and reasonable broodstocks mating and seedling production strategies should be carried out in the future to maintain the genetic diversity level of Chinese farmed population of southern flounder. Moreover, selective breeding program should be in process soon in order to ensure sustainable development of farming industry of southern flounder in China.