Abstract:

Oncorhynchus mykiss was cultured all over the world, this paper analyzed the genetic variation of MHC\|DAB intron 2 sequences (308 bp) in Gansu golden trout, Donaldson rainbow trout and USA Golden trout using PCR\|SSCP. 11 different nucleotide sequences（Ⅰ~Ⅺ）were detected from 108 positive clones, a maximum of 4 alleles were amplified from one single individual. Allele Ⅱ, Ⅲ and Ⅵ were presented in all the 3 populations. Ⅳ was only presented in Donaldson rainbow trout; Ⅶ only presented in Gansu golden trout; Ⅸ, Ⅹ and Ⅺ only presented in Golden trout. In Gansu golden trout, Donaldson rainbow trout and Golden trout, the nucleotide polymorphic sites were 17, 19 and 22. The nucleotide diversities (Pi) were 0.005, 0.008 and 0.013. The average numbers of nucleotide differences (K) were 1.200, 2.000 and 3.333, respectively. The genetic distance of Gansu golden trout and Donaldson rainbow trout was the smallest (0231), while that of Gansu golden trout and Golden trout was the largest (0.539). The genetic differentiation that compared any 2 of the 3 populations all up to the standard of population division (D＞0.05). The genetic differentiation index (GST) of the 3 populations was 0.097, indicating that the variation mainly came from the inter\|individual of the population.

Key words: Oncorhynchus mykiss, genetic structure, genetic differentiation, MHC

摘要：

虹鳟是当前全球性养殖品种，采用PCR\|SSCP的方法，分析了甘肃金鳟、道氏虹鳟和美国金鳟三个虹鳟养殖群体各30个个体MHC\|DAB基因第2内含子序列（308 bp）的遗传变异。108个阳性克隆经SSCP筛选及测序，共获得11种不同的核苷酸序列（Ⅰ~Ⅺ），单个个体最多存在4种等位基因。等位基因Ⅱ、Ⅲ、Ⅵ是三个群体共有的；Ⅳ仅存在于道氏虹鳟中；Ⅶ仅存在于甘肃金鳟中；Ⅸ、Ⅹ、Ⅺ仅存在于美国金鳟中。甘肃金鳟、道氏虹鳟、美国金鳟群体内核苷酸多态位点分别为17个、19个、22个，核苷酸多样性指数（Pi）分别为0.005、0.008、0.013，平均核苷酸位点差异数（K）分别为1.200、2.000、3.333。甘肃金鳟群体与道氏虹鳟群体间的遗传距离最小(0.231)，与美国金鳟群体间的遗传距离最大(0.539)，三个群体间的遗传分化均达到了种群的分化标准（D＞0.05）。群体遗传分化系数GST为0.097，表明变异主要来源于群体内个体间。

关键词: 虹鳟（Oncorhynchus mykiss）；遗传结构；遗传分化；MHC