We evaluated the genetic diversity among four rainbow trout strains at 30 microsatellite loci. In addition, we compared the genetic diversity in these strains with that of samples collected in 2005 to evaluate the genetic differentiation attributable to selection pressure. All 30 microsatellite loci are suitable markers of genetic diversity in the four rainbow trout strains. The mean number of alleles in the four strains varied from 3.77 to 5.80; the mean number of effective alleles varied from 2.746 1 to 3.630 3; the mean expected heterozygosity ranged from 0.590 6 to 0.722 1,the mean observed heterozygosity ranged from 0.587 5 to 0.786 1,and the mean polymorphism information content ranged from 0.535 0 to 0.647 0. All four rainbow trout strains exhibited a high level in genetic diversity. Analysis of the genetic distance revealed that Finland rainbow trout and Norway rainbow trout cluster together and the two Golden trout cluster together. When compared with the samples acquired in 2005,Norway rainbow trout and American golden trout have significantly lower allele numbers, effective allele numbers, and polymorphism information content(P0.01), but there was no difference for Finland rainbow trout.% 利用30个微卫星标记分析了虹鳟mykiss)4个品系，即芬兰虹鳟、挪威虹鳟、美国金鳟及日本金鳟的遗传多样性，并对部分品系2005年及2011年采集的样品进行了比较分析，揭示了在养殖及育种的选择压力下同品系虹鳟的遗传多样性的变化趋势。结果表明：①30个微卫星标记均可用于4个虹鳟品系的种质鉴定；②4个品系的平均等位基因数为3.77~5.80，平均期望杂合度为0.5906~0.7221,平均观察杂合度为0.5875~0.7861,平均多态性信息含量为0.5350-0.6470,说明4个品系均属高度多态，遗传多样性较高；③计算4个虹鳟品系遗传距离，并进行聚类分析，芬兰虹鳟与挪威虹鳟先聚为一类，美国金鳟与日本金鳟聚为一类；④检测3个虹鳟品系的遗传多样性变化趋势，挪威虹鳟、美国金鳟2011年样本等位基因数、有效等位基因数、多态性信息含量显著低于2005年样本(P<0.01),芬兰虹鳟遗传参数也有所下降，但差异不显著。本研究旨在对虹鳟养殖、种质资源鉴定与保护提供参考依据。
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