荷斯坦牛HSP70-1和HSP32基因SNP位点与生产性能及乳房炎抗性的相关性研究

Single nucleotide polymorphism of HSP70-1 and HSP32 gene and correlation with production traits and mastitis resistance in Chinese Holstein

利用测序、巢式PCR(Nest-PCR)和限制性片段多态性PCR(restriction fragment length polymorphism,PCR-RFLP)方法,检测375头中国荷斯坦牛热休克蛋白70-1(heat shock protein 70-1,HSP70-1)和热休克蛋白32(HSP32)基因的编码区单核苷酸多态性(single nucleotide polymorphism,SNP)位点,并分析其基因多态与生产性能及乳房炎抗性的相关性。结果表明:HSP70-1基因的3 099 bp和HSP32基因的6 356 bp位点都发生了G→A突变,这2个位点均是沉默突变,未引起氨基酸序列的改变;经χ2适合性检验,试验牛群在2个位点均未达到Hardy-Weinberg平衡状态;群体基因座不同基因型与体细胞评分、乳脂率、乳蛋白、成年当量相关性分析的结果表明,HSP70-1和HSP32的SNP位点与乳脂率、乳蛋白、成年当量相关性不显著,HSP32 SNP位点基因型与体细胞评分相关性显著(P=0.041),HSP70-1 SNP位点基因型与体细胞评分相关性不显著(P=0.053)。两基因型组合分析发现,HSP70-1的GG型和HSP32的AA型为最佳组合,其体细胞评分显著或极显著低于其他组合,可将该组合作为抗乳腺炎性状的分子遗传标记。

DNA sequencing, Nest-PCR and restriction fragment length polymorphism（ PCR-RFLP）were used to investigate mutations in the coding region of heat shock protein 70-1 （HSP70-1） and HSP32 gene in 375 Chinese Holstein dairy cows, and the associations between the polymorphisms and production traits and mastitis resistance were analyzed. The G→A mutation at 3 099 bp in HSP70-1 gene and G→A mutation at 6 356 bp in HSP32 gene were found and both of them were silence mutations that caused no alteration in amino acid sequence. Chi-square test showed both loci were not in Hardy-Weinberg equilibrium in Chinese Holstein. In the meanwhile, the associations between the polymorphisms and all production traits, except SCS, were not significant. The polymorphism in HSP32 gene affected somatic cell score（SCS） significantly（P=0.041 ）, however, the association between the HSP70-1 polymorphism and SCS was not significant （ P = 0. 053 ）. After analyzing the relation between SCS and combined genotypes, the result showed that the combination of HSP70-1 genotype GG and the HSP32 genotype AA was the best one, the SCS of this combination was lower than almost all other combinations significantiy or very significantly,so this combination may be used as a molecular and genetic marker to improve the phenotype of anti-mastitis in Chinese Holstein dairy cows.