荷斯坦牛HSP70-1基因遗传多态性与乳腺炎抗性关系

以253头中国荷斯坦奶牛为研究对象, 检测HSP70-1基因的多态性, 并分析其多态性与中国荷斯坦牛体细胞评分(Somatic cell score, SCS)的相关性。首先以PCR-SSCP法寻找HSP70-1基因编码区的突变, 并通过测序确定突变的类型, 根据突变类型寻找合适的内切酶, 最终采用PCR-RFLP方法鉴定实验牛基因型; 然后分析基因多态性与中国荷斯坦牛SCS的相关性。结果表明HSP70-1基因的1 623 bp处产生G→A→C突变, 2 409 bp处产生G→A突变, 两位点都是沉默突变, 未引起氨基酸序列的改变; 经χ2 适合性检验, 中国荷斯坦牛在两个位点均未达到Hardy-Weinberg平衡状态; 同时, 群体基因座不同基因型与SCS相关分析的结果表明, 2409位点基因型与SCS相关性不显著(P>0.05), 1623位点基因型与SCS相关性显著(P<0.05), CC型SCS显著低于AG、GG型(P<0.05), CC基因型为乳腺炎抗性基因型。在中国荷斯坦奶牛群体中, HSP70-1基因CC基因型可作为改良奶牛乳腺炎抗性性状的分子遗传标记。

Research on Polymorphism of HSP70-1 gene in Holstein and the Relationship between Different Genotypes and Resistance to Dairy Mastitis

he polymorphisms of HSP70-1 gene in 253 Chinese Holstein dairy cows were studied, and the association between the polymorphisms and somatic cell score (SCS) were analyzed. PCR-SSCP, PCR-RFLP and DNA sequencing were used to investigate mutations in the coding region of HSP70-1 gene. The G→A→C mutation at 1 623 bp and G→A mutation at 2 409 bp were found and both of them were silence mutations that caused no alteration in amino acid sequence. Chi-square test showed both loci weren′t at Hardy-Weinberg disequilibrium in Chinese Holstein. In the meanwhile, the association of 2 409 locus and SCS was not significant. However, the polymorphism at 1623 locus affected SCS signifi-cantly (P<0.05). The SCS of genotype CC was significantly lower than that of genotype AG and GG (P<0.05), so genotype CC was mastitis resistant. These results suggest that genotype CC of HSP70-1 gene may be used as a molecular and genetic marker to improve the phenotype of anti-mastitis in Chinese Holstein dairy cows.