摘要： 利用PCR－RFLP方法检测TLR2基因在297头中国荷斯坦牛中的多态性，并分析其多态性与体细胞评分(SCS)的相关性。结果表明，TLR2基因exon2 扩增片断的109 bp处产生C→A的突变，并导致天冬氨酸突变为谷氨酸。TLR2基因exon2被EcoR V 消化后表现多态性，表现AA，AB，BB 3种基因型，其中B等位基因为优势等位基因，等位基因频率为0.78 5，而A等位基因频率则为0.215 5.经χ2 适合性检验，中国荷斯坦牛在该位点达到Hardy－Weinberg平衡状态。同时，群体EcoR V基因座不同基因型与SCS相关分析的结果表明，BB，AB型个体的SCS指标显著高于AA型(p＜0.05)，AA基因型可作为乳腺炎抗性的有利基因型，可将TLR2作为奶牛乳腺炎候选基因，将应用于分子标记辅助选择育种，为乳腺炎抗性牛群的选育奠定一定的理论基础。

关键词: TLR2, PCR－RFLP, 体细胞评分, 乳腺炎抗性, 中国荷斯坦牛

Abstract: In this research,polymorphisms ofTLR2gene in Chinese Holstein(n=297)were detected with PCR-RFLP,and relationship between polymorphisms of TLR2 with somatic cell score(SCS)was analyzed.Results showed that a polymorphic site was identified,where there was a mutation C→A at position 106 bp after sequencing,which resulted in Asp replaced by Glu.Genotype AA,AB and BB were detected by digesting the fragment with restriction endonucLeaseEcoR V in the population.B allele was predominant and allele frequency A and B were estimated as 0.784 5,0.215 5.χ²test indicated that the polymorphism locus in Chinese Holstein fitted Hardy-Weinberg equilibrium(p<0.05).In addition,the effect of theTLR2polymorphism on SCS was analyzed.Results indicated that the SCS of BB and AB genotype cows were significantly higher than AA genotype(p<0.05).AA genotype was beneficial to mastitis resistance.We concluded thatTLR2gene could be candidate gene of mastitis resistance for molecule marker-assisted selection breeding.This study might offer a theoretical basis on selection of the mastitis resistance in Holstein cattle.

Key words: TLR2, PCR-RFLP, Somatic cell score, Mastitis resistance, Chinese Holstein cattle

中图分类号: 

• S823