采用PCR-SSCP方法对中国美利奴羊和哈萨克羊中IGFBP-3基因的多态性进行了检测, 并对不同基因型与中国美利奴羊部分羊毛性状间的关联性进行了分析。结果在位于内含子1区的一段178 bp的扩增产物经SSCP分析后出现了3种基因型, 基因型AA、AB和BB及等位基因A、B在中国美利奴羊中的频率分别为0.70、0.24、0.06和0.82、0.18; 在哈萨克羊中的频率分别为0.87、0.13、0.00和0.93、0.07。序列分析发现: 在该序列的122位碱基表现多态性 (g.122 G>T)。所研究的两个群体在该位点上均处于Hardy-Weinberg不平衡状态(P<0.01)。不同基因型对部分羊毛性状有一定的影响: 不同基因型个体在剪毛后体重和净毛率上没有明显差异。AA、AB及BB基因型个体的羊毛伸直长度逐渐变短, 其中AA与AB基因型之间差异极显著(P<0.01)。AA型个体的剪毛量和羊毛密度要明显低于AB型(P<0.01)和BB型个体(P<0.05); 羊毛纤维直径则明显高于AB型(P<0.01)和BB型(P<0.05)个体。

In this study, PCR-SSCP analysis was used to identify genetic variation in IGFBP-3 gene in Chinese Merino and Kazakh sheep. A PCR product of 178 bp corresponding to partial intron1 illustrated three unique binding patterns by SSCP analysis. Frequencies of the genotype AA, AB, BB and allele A, B in Chinese Merino sheep were 0.70, 0.24, 0.06, and 0.82, 0.18 respectively , and they were 0.87, 0.13, 0.00, and 0.93, 0.07 respectively in Kazaka sheep. Sequence analysis revealed a G/T transversion at position 122 of the fragment. This polymorphic locus of IGFBP-3 gene was at Hardy-Weinberg dis-equilibrium (P<0.01) in the two breeds. Different genotypes slightly affected several wool traits of Chinese Merino sheep. The individuals of genotype AA, AB, and BB had no significant difference in post-shearing weight and clean wool rate. Sta-ple length (SL) was decreased with the genotype of AA, AB, and BB, and the difference between AA and AB was significant (P<0.01). Greasy fleece weight (GFW) and follicle density in individuals of genotype AA was significantly lower than that in individuals of genotype AB (P<0.01) and BB (P<0.05); Average fiber diameter (AFD) in individuals of genotype AA was significantly higher than that in individuals of genotype AB (P<0.01) and BB (P<0.05).