Novel single nucleotide polymorphisms (SNPs) of the bovine STAT4 gene and their associations with production traits in Chinese Holstein cattle

Signal transducer and activator of transcription 4 (STAT4) belongs to the STATs family which may play important roles in the activation of milk protein genes and the development of mammary glands. Four novel single nucleotide polymorphisms (SNPs) (g.2624A>C ss175327225, g.60330A>G ss175327226, g.63823G>C ss175327227, g.66912C>T ss175327228) of the STAT4 gene were investigated in 966 cattle of three breeds (Chinese holstein, Luxi yellow and Bohai black cattle) in China by polymerase chainreaction-single-strand conformation polymorphism (PCR-SSCP), PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing methods. The SNP (g.60330A>G ss175327226) could be genotyped into three genotypes (AA, AG and GG) with PCR-RFLP using Msp I and another SNP (g.66912C>T ss175327228) only into two genotypes (CC and TC) by PCR-SSCP. The allelic frequencies of the SNP (g.60330A>G) were different among the three different cattle breeds (P < 0.05). The associations between polymorphisms of the STAT4 gene and dairy performance traits were analyzed in 793 Chinese holstein cows. The SNP (g.60330A>G) markedly affected the 305 d matured equivalency (P < 0.05) and fat content (P < 0.05). However, the SNP (g.66912C>T) had no significant relationship with the milk production traits (P > 0.05). Together, the SNP (g.60330A>G) of the STAT4 gene may serve as a molecular marker for the differentiation of various cattle populations and selection of the milk yield and fat content in bovine breeding program