摘要：
研究分析了12对大口鲇(Silurus meriaionalis)微卫星标记引物在兰州鲇(Silurus lanzhouensis)、鲇(Silurus asotus)及革胡子鲇(Clarias fuscus)各群体间通用性.结果表明,大口鲇微卫星标记引物除位点DQ223147、DQ223160扩增无特异性条带,位点DQ223149、DQ223159无多态性外,其余8对在这几种鲇形目鱼类中具有较高的通用性,每个位点等位基因数为2-15个不等；不同重复拷贝类别的位点以富含AC重复单元的等位基因数较多,多态性比较丰富.4个群体平均观测杂合度为0.7571,平均期望杂合度为0.6870,平均多态性信息含量0.6441,均为高度多态,说明这8个位点适用于鲇形目鱼类的遗传学研究.采用Nei's遗传距离(D)绘制NJ系统发育树,4个群体聚成两大类,兰州鲇与鲇群体先聚类后和大口鲇聚为一大类,革胡子鲇聚为另一大类.8个有效微卫星位点中3个具有特异基因型的稀有等位基因位点(DQ223146、DQ223151与DQ223173),可区分4种鲇形目鱼类,作为其种质鉴定的标记位点.借用已有鲇形目鱼类遗传标记资源,增加同目鱼类遗传连锁图谱上遗传标记的密度,将对今后开展鲇形目鱼类种质资源保护及分子育种奠定坚实基础.%Twelve microsatellite markers from Silurus meriaionalis were selected to analyze the application on four closely related species of siluriformes including S. Meriaionalis, S. Lanzhouensis, S. Asotus and C. Fuscus. Among the twelve microsatellite markers, eight microsatellite loci had high versatility, and the number of alleles per locus ranged from 2 to 15. The loci with AC repeat motif had more allele, on which the polymorphisms were higher than others. The other four loci either had no specific amplification bands (DQ223147 and DQ223160), or no polymorphism (DQ223149 and DQ223159). The average value of observed heterezygosity (Ho) was 0.7571; the average of expected heterezygosity (He) was 0.6870; and the polymorphism information content (PIC) was 0.6441. Taken together, the values indicated the eight locis were highly polymorphic, therefore suitable for siluriformes genetics research. In addition, phylogenetic tree constructed by Nei's-genetics distance divided four species of siluriformes into two groups, one included S. Lanzhouensis and 5. Asotus, the other contained S. Meriaionalis and C. Fuscus. Three rare genotype-specific locis (DQ223146, DQ223151 and DQ223173), among 8 effective locis, could be employed to identify the 4 species of siluriformes. Therefore, they add density of genetic markers on genetic linkage map. More important, it would construct solid foundation for siluriformes germplasms protection and molecular breeding.
