Polymorphism identification in goat DGAT1 and STAT5A genes and association with milk production traits

Polymorphisms of DGAT1 and STAT5A genes in Xinong Saanen and Guanzhong goat breeds were investigated. PCR-RFLP, SSCP, and DNA sequencing were used to identify three SNPs: DQ380250:g.407_408insC in the DGAT1 gene, AJ237937:g.6798C>T and g.6852C>T in the STAT5A gene. In DGAT1 g.407_408insC locus, the frequencies of C- allele were 0.79-0.85, and frequencies of C+ allele were 0.21-0.15. At STAT5A g.6852C>T locus, frequencies of C allele were 0.70-0.72, and frequencies of T allele were 0.30-0.28. Compared with goats with DGAT1 C-C-, those with C-C+ genotype had greater milk fat (P < 0.05). The goats with STAT5A CT had greater milk yield than those with CC genotype (P < 0.05). The results showed that does with C-C-CT and C-C+CT yielded more milk than those with C-C-CC(P < 0.05). In addition, does with C-C+CT had the highest milk fat in comparison with other combination genotypes (P < 0.05).