WU Enyun, REN Wenwen, LI Yaodong, LIU Lixia, CAO Xin, ZHANG Li
In order to investigate the association between Toll like receptor 1 (TLR1) gene and mastitis resistance in Chinese Holstein cattle, a DNA pooling was constructed in Chinese Holstein cattle. The single nucleotide polymorphism (SNP) of TLR1 gene of Chinese Holstein cattle was detected by PCR amplification and direct sequencing, and the SNPs loci which had a significant effect on the immunity of Chinese Holstein cattle were screened. At the same time, the online software was used to predict the function of the protein encoded by the TLR1 gene of Chinese Holstein cattle. The results showed that Chinese Holstein TLR1 gene encodes 727 amino acids and constitutes an unstable water-soluble protein. After PCR amplification, a total of 8 SNPs loci were found in the amplified fragments, namely A61T-TLR1, C632A-TLR1,C1408T-TLR1, C1451T-TLR1, A1461G-TLR1, A1475C-TLR1, G1550A-TLR1 and G1596A-TLR1. Among them, C632A-TLR1, C1451T-TLR1, A1461G-TLR1, A1475C-TLR1 and G1596A-TLR1 resulted in missense mutation. The allele frequencies of SNPs loci with five missense mutations were mutated from the original lysine(Lys), phenylalanine(Phe), alanine(Ala), isoleucine(Ile), andvaline(Val) to methionine(Met), leucine(Leu), valine(Val), valine(Val) and isoleucine(Ile), and the allele frequencies of the five missense mutation SNPs were slightly different before and after the mutation, and the rest are significantly different. The DNA pooling combined with direct sequencing technology to detect 8 SNPs of TLR1 gene, which can be used as a genetic marker for Chinese Holstein cow mastitis. The results of protein function prediction show that there are many factors associated with immune related factors. The results of this study provide a theoretical basis for the resistance breeding of Chinese Holstein cattle in molecular field.