中国荷斯坦牛TLR1基因启动子区SNP多态与乳房炎抗性和泌乳性状的关联分析

摘要

Toll like receptor 1 (TLR1) is one of the important immune genes for cattle (Bos taurus),which has significant effects on immune recognition and inflammatory reponse.To investigate the correlation between the SNPs in the promoter region of TLR1 gene and somatic cell score (SCS),clinical mastitis (CM) and milking traits for Chinese Holstein cattle,the SNP in the promoter region of TLR1 gene was screened by PCR and direct sequencing for 20 cows with low SCS and 20 cows with high SCS.Finally,TLR1-245 G＞T for 866 Chinese Holstein cattle were detected using flight mass spectrometry.The SCS,CM and milking traits of tested cattles were collected from the management system of dairy farm.The correlation between the SNPs and these traits of tested cattles was analyzed using multi-factor variance analysis.The results showed that only one transcription factor binding site for TLR1-245 G＞T site (TATA binding protein,TBP) was found.The dominant genotype and gene of TLR1-245 were GT and T,and their frequencies were 0.487 and 0.584,respectively.The distribution of genotype was in the Hardy-Weinberg equilibrium.TLR1-245 G＞T showed extremely significant correlation with test-day milk yield (TDMY) and SCS (P＜0.01),and no significant correlation with fat content (FC),protein content (PC),lactose content (LC),total solid (TS) and milk urea nitrogen (MUN) (P＞0.05).The individuals cattles with TT genotype had higher TDMY than that of GG and GT,and individuals cattles with GG genotype had the lowest TDMY.The SCS for individuals cattles with GG genotype were significantly higher than that of GT and TT genotype (P＜0.05).TLR1-245 G＞T showed significant correlation with the number of cattle suffering from CM (P＜0.05),and the number of cattle suffering from CM for individuals with TT genotype was significantly lower than that of GG and GT genotype (P＜0.05).These results provide a reference for the increase of milk yield and the control of SCS in Chinese Holstein cattles.%Toll样受体1(Toll like receptor 1,TLR1)基因是牛(Bos taurus)重要的免疫基因之一,在免疫识别、炎症反应等方面有重要作用.为探讨TLR1启动子区SNP突变与中国荷斯坦牛乳中体细胞评分(somatic cell score,SCS)、临床乳房炎(clinical mastitis,CM)和泌乳性状的相关性,本研究根据TLR1基因启动子区序列,利用PCR-直接测序法对低SCS和高SCS各20个样本进行SNP筛查,将筛选到的TLR1-245 G＞T利用飞行质谱法对866头中国荷斯坦牛进行检测,同时收集所检测牛只临床乳房炎发生情况、SCS和泌乳性状等信息,利用多因素方差分析SNP位点突变对相应指标的影响.结果表明,TLR1基因启动子区700 bp范围内只发现TLR1-245 G＞T 1个SNP突变;TLR1-245 G＞T与中国荷斯坦牛日产奶量及SCS极显著相关(P＜0.01),与乳脂率、乳蛋白率、乳糖、总固体以及尿素氮含量无显著相关(P＞0.05),GG型个体日产量及SCS均显著低于GT和TT型个体(P＜0.05).TLR1-245 G＞T与奶牛患临床乳房炎次数显著相关(P＜0.05),TT型个体患临床乳房炎次数显著低于GG和GT型个体(P＜0.05).研究结果为提高中国荷斯坦牛产奶量和控制乳中体细胞数的分子标记选择提供了参考资料.