乌苏里拟鲿野生群体和人工养殖群体遗传多样性的比较研究

Genetic diversity analyses of wild and cultured Pseudobagrus ussuriensis populations

采用SRAP分子标记技术对乌苏里拟(Pseudobagrus ussuriensis)1个野生群体(采自江苏省洪泽湖)和2个人工养殖群体(分别采自淮安市水产研究所F2代和苏州市东山水产养殖场F3代)进行了遗传多样性的比较。结果显示:从100组引物组合中筛选出12组条带清晰、多态性好的引物组合,每个引物组合检测到11～17个位点数,在乌苏里拟三个群体中共检测到202个位点,其中多态位点有130个,多态位点比例为64.36%。野生群体与2个人工养殖群体(淮安市水产研究所F2代,苏州市东山水产养殖场F3代)多态位点比例分别为63.13%、56.54%、54.88%;Nei's基因多样性指数(H)分别为0.2641、0.2546、0.2469;Shannon's信息指数(I)分别为0.4118、0.4050、0.3861;野生群体与2个人工养殖群体的遗传距离分别为0.1730、0.1104;两个人工养殖群体间的遗传距离为0.1087。以上结果表明,野生乌苏里拟鲿群体的遗传多样性水平最为丰富,而人工养殖群体遗传多样性有所下降。比较各扩增位点显性基因型频率在不同区间的分布发现,人工养殖群体低频位点明显减少而隐性纯合基因位点显著增加。群体遗传结构分析表明,野生群体与2个人工养殖群体的Nei's基因多样性指数(H)、Shannon's信息指数(I)及遗传距离相近,群体遗传结构相似,养殖群体尚未形成独立的遗传结构。因此,在未来乌苏里拟鲿人工繁殖时应选用足够大的、有代表性的亲本群体,在保持优良性状的同时最大限度的保留群体的遗传多样性。

The sequence-related amplified polymorphism（SRAP） molecular marker technique was used to compare genetic structures of three populations（one wild and two cultured） of Pseudobagrus ussuriensis.Samples of wild population were collected from Jiangsu Hongze Lake and the two cultured populations from Fisheries Research Institute of Huaian（F2 generation） and Suzhou Dongshan Aquatic Breeding Plants（F3 generation）.Twelve pairs of SRAP primers were selected from 100 primer combinations.Two hundred and two amplified loci were obtained from the three populations,among which 130 were polymorphic.The percentage of polyrnorphic loci in the Hongze Lake（HL） population,Huaian populations（HA）,Suzhou Dongshan populations（SZ） was 63.13%,56.54% or 54.88%,respectively.The results indicated that genetic polyrnorphism decreased in two cultured populations.The Nei＇s gene diversity of three populations was 0.2641,0.2546 or 0.2469,respectively;the Shannon＇s Information index of three populations was 0.4118,0.4050 or 0.3861,respectively.The genetic distance between wild population and two cultured ones were 0.1730 and 0.1104,while the genetic distance between two cultured ones was 0.1087.The noticeable decrease in the number of rare loci and the increase in the number of homozygous recessive loci in the cultured population suggested a considerable loss of low frequency alleles in the cultured populations,which might have resulted from small effective population sizes during artificial seed production.In the future P.ussuriensis artificial propagation should be chosen to large sufficiently and representative parent groups to maintain the good traits to retain maximum genetic diversity.