title: Haplotype analysis of TLR4 gene and its effects on milk somatic cell score in Chinese commercial cattle.
abstract: Bovine mastitis is a very complex and common disease of dairy cattle and a major source of economic losses to the dairy industry worldwide. In this study, the bovine TLR4 was taken as a candidate gene for mastitis resistance. This study aimed to analyze the associations of single nucleotide polymorphisms (SNP) or haplotype and somatic cell score (SCS) in 404 Chinese commercial dairy cattle including Chinese Holstein, Sanhe cattle and Chinese Simmental breeds. The polymerase chain reaction and sequencing methods were used for detecting genotype and allele frequency distribution of the two SNPs (rs8193062, rs8193064), statistical results showed that T allele at rs8193062 and C allele at rs8193064 were the predominate alleles. Moreover, six SNPs, including two SNPs (rs8193062, rs8193064) and four SNPs (rs8193060, rs8193069, rs29017188, rs8193046) which were chosen according the polymorphism level for the same cattle populations in previous studies, were used for haplotype analysis, the results revealed that twenty-one haplotypes were found in the mentioned animals, of which, Hap1 (30.5 %) and Hap2 (30.4 %) were the most common haplotypes. Hap2, Hap4 and Hap12 might negatively effect on milk SCS, whereas Hap13 might positively effect on milk SCS. The results in this study might assist in marker assisted selection and provided some reference to be implemented in breeding programs to improve the mastitis resistance of dairy cattle.
authors.affiliation: Key Laboratory of Zoology in Hunan Higher Education, College of Life Science, Hunan University of Arts and Science, Changde, 415000, People's Republic of China.
authors.forename: Xing Ping
authors.initials: XP
authors.lastname: Wang
authors.forename: Zhuo Ma
authors.initials: ZM
authors.lastname: Luoreng
authors.forename: Shu Xin
authors.initials: SX
authors.lastname: Gao
authors.forename: Dong Sheng
authors.initials: DS
authors.lastname: Guo
authors.forename: Jun Ya
authors.initials: JY
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Gao
authors.forename: Shang Zhong
authors.initials: SZ
authors.lastname: Xu
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Jin Ren
authors.initials: JR
authors.lastname: Wang
mesh_terms: D000483:Alleles; D000818:Animals; D001947:Breeding; D002417:Cattle; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D008414:Mastitis, Bovine / Q000235:genetics / Q000473:pathology; D008892:Milk / Q000166:cytology*; D020641:Polymorphism, Single Nucleotide; D051197:Toll-Like Receptor 4 / Q000235:genetics*
chemical_list: D051197:Toll-Like Receptor 4