以采自四川省汉源县的野生稀有(鲍)鲫(Gobiocypris rarus)50对为建群原代(P0),采用最佳避免近交法建立了封闭群Ihb∶ IHB.应用11对微卫星引物对原代、F1-F4代传代亲鱼进行了遗传多样性监测.11个微卫星位点在稀有(鲍)鲫野生型封闭群共发现等位基因57个,各位点平均等位基因数5.2个、平均有效等位基因数3.3个、平均多态信息含量0.5282.封闭群各代平均期望杂合度为0.5553-0.5742,平均多态信息含量范围为0.5060-0.5318,平均观察等位基因数、平均有效等位基因数、平均观察杂合度、平均期望杂合度、平均多态信息含量在各代之间均无显著性差异(P＞0.05).各代间的遗传相似性在0.99以上,遗传分化系数FST为0.0008(P＞0.05),基因频率也无显著性差异(P＞0.05).监测结果表明,Ihb∶ IHB保持了野生种群的遗传多样性,建群传代过程中未出现显著的遗传分化,符合实验动物封闭群的要求,可以作为一个实验动物的新品系.%Gobiocypris rants is a small freshwater fish endemic to upper reaches of the Yangtze River. In China, the fish is being used as an aquatic laboratory animal mainly applied in researches on toxicology, fish pathology and genetics. Due to habitat loss and human activities, G. Rants is also considered as an endangered species listed in the China Red Data Book of Endangered Animals. Closed colony is an animal stock propagated by non-inbred within the stock, in which no genes are introduced from outside the stock from generation to generation. Because of high heterozygosity and stable genetic structure, closed colony animals are widely used in various researches. Therefore, foundation of a closed colony of G. Rams is the basis for its future laboratory use as well as species conservation. In the present study, we established a closed colony of G. Rants with 50 pairs of wild fish (P0) gathered in Hanyuan County, Sichuan Province. The stock propagated by maximum avoidance of inbreeding system for 4 generations (F1 to F4) was named as Ihb: IHB. Eleven microsatellite loci were used to monitoring the genetic variation among the generations. A total of 57 alleles were detected in the overall sample, while the number of alleles per locus, the effective number of alleles and the polymorphic information (PIC) averaged 5.2, 3.3 and 0.5282, respectively. For different generations of the closed colony, average expected heterozygosity (He) ranged from 0.5553 to 0.5742, and average PIC ranged from 0.5060 to 0.5318. No significant differences (P>0.05) on genetic diversity indices were detected among generations, including the averaged observed number of alleles (Na), average effective number of alleles (Ne), average observed heterozygosity (Ho), aver age expected heterozygosity (He) and average polymorphic information (PIC). Pairwise genetic similarities were over 0.99, implying closer genetic relationship and high genetic identity among generations. Analysis of molecular variance (AMOVA) revealed pairwise fixation index (FST) ranged from 0.0001 to 0.0031 with the overall FST value 0.0008 among generations, indicating that most of the genetic variance was among individuals rather than that of generations. Fisher's exact test on allele frequency showed no significant difference on any loci in successive generations (P>0.05). As a result, the genetic variation during the propagation of generations of G. Rarus was successfully avoided and then high genetic diversity of the wild population was maintained in the strain. In other words, it indicated that Ihb: IHB of G. Rarus fit the genetic quality of closed colony animal. Continuous reproductive strategy and genetic monitoring program should be carried out in order to use this newly established closed colony.
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