TLR2基因多态性与奶牛体细胞评分的相关性研究

摘要

This present study was aimed to investigate the effect of TLR2 on sub-mastitis in bovine. 15 Holstein and Xinjiang Brown cattle with the highest and lowest SCS were chosen to sequence the TLR2 gene, respectively, and then the SNP sites were detected with PCR-RFLP. Finally, the associations between genotypes and SCS were analyzed. The results showed that: (1)3 SNP sites (E+189, E+631 and E+2260) were discovered in TLR2. (2) At E+189 site of TLR2, the SCS of individuals with BB genotype was lower than that of individuals with AA and AB genotypes (P＜0. 05). It suggested that BB genotype played an important role in mastitis resistance of cattle. (3) At E+631 site of TLR2, SCS of individuals with BB genotype was lower than that of individuals with AA genotype, but not significant (P＞0. 05). (4) When E+2260 site was mutated and translated into termination codon, the SCS of individuals with AB genotype increased. It indicated that this mutation was harmful to mastitis resistance of cattle. (5) The SCS in Xinjiang Brown cattle was lower than that in Holstein. It indicated that mastitis resistance of Xinjiang Brown cattle was stronger than that of Holstein. (6) Mutation rate of three sites (E +189, E+631 and E+2260) in Xinjiang Brown cattle were higher than that in Holstein(P＜0. 01). Conclusion: E+189 and E+631 SNP sites affect the mastitis resistance of cattle. The possible reason of the stronger resistance in Xinjiang Brown cattle is that there are some difference in distribution of two breeds between E+189 and E+631 sites.%旨在分析Toll-样受体2在奶牛隐性乳房炎中的作用.本研究以同一牛场内的中国荷斯坦奶牛和新疆褐牛为研究对象,选取奶牛体细胞数小于20万和大于100万的个体各15头,对TLR2基因进行测序,然后对发现的多态位点进行PCR-RFLP检测,分析这些位点与体细胞评分(SCS)的相关性.结果发现了TLR2基因E+189、E+631和E+2260 3个SNP位点,其中E+631和E+2260位点为本试验首次发现.E+189、E+631和E+2260 3个SNP位点在2个品种内均处于Hardy-Weinberg平衡状态(P＞0.05);3个位点在2个品种间的基因型分布差异都极显著(P＜0.01).分析每个SNP位点与SCS的相关性,显示TLR2 E+189位点AA比BB和AB基因型个体的SCS高(P＜0.05),AB与BB基因型个体的SCS差异不显著(P＞0.05);说明BB基因型个体的乳房炎发病率低.而TLR2 E+631的SCS和TLR2 E+189位点表现相似,但各个基因型个体间的SCS差异不显著(P＞0.05).E+2260位点AA基因型个体比AB的SCS低(P＞0.05).新疆褐牛的SCS低于荷斯坦牛(P＜0.01),说明新疆褐牛乳房炎发病率比荷斯坦牛低.在发现的3个SNP位点中,E+189位点对奶牛的SCS有显著影响(P＜0.05),TLR2基因SNP位点在2个品种内的分布差异可能是新疆褐牛比荷斯坦牛乳房炎发病率低的原因之一.