Analysis of Polymorphism of TLR2 Gene and the Relationship between the Gene and Mastitis Resistance in Chinese Holstein Cattle

In this research,polymorphisms of TLR2 gene 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 endonuclease EcoR V in the population.B allele was predominant and allele frequency A and B were estimated as 0.784 5,0.215 5.χ2 test indicated that the polymorphism locus in Chinese Holstein fitted Hardy-Weinberg equilibrium(p0.05).In addition,the effect of the TLR2 polymorphism on SCS was analyzed.Results indicated that the SCS of BB and AB genotype cows were significantly higher than AA genotype(p0.05).AA genotype was beneficial to mastitis resistance.We concluded that TLR2 gene 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.