Novel SNPs of butyrophilin (BTN1A1) and milk fat globule epidermal growth factor (EGF) 8 (MFG-E8) are associated with milk traits in dairy goat

Butyrophilin (BTN1A1) and milk fat globule epidermal growth factor (EGF) 8 (MFG-E8) genes are both milk fat globule membrane proteins. BTN1A1 plays a key role in the secretion of milk lipid and production which has effects on performance traits, while the MFG-E8 is vital for the development of the mammary gland and phagocytic clearance of apoptotic cells. Therefore, BTN1A1 and MFG-E8 gene are candidate genes for quantitative traits in mammalian animals with respect to milk performance traits. The objective of this study is to investigate variations in goat BTN1A1 and MFG-E8 gene and analyze their associations with growth trait and milk performance. In this study, the goat BTN1A1 gene showed a novel single-nucleotide polymorphism (SNP): XM_001494179:g.8659C > T, resulting in a missense mutation: CTT (Leu)> TTT (Phe) at position 377 aa of the BTN1A1 (526 aa); the goat MFG-E8 gene showed four novel SNPs: NC_007319: g.843delA, 6417delC, 14892T > C and 14996A > C, only the 14892T > C result in a synonymous mutation. The associations between genotypes and production traits were analyzed. Significant statistical results implied that HinfI locus of BTN1A1 gene is associated with milk fat yield (P = 0.004), total solid (P = 0.002), solid-non fat (P = 0.018) and first milk yield (P = 0.030). The DA and EcoRV loci of MFG-E8 gene are associated with milk fat yield (DA locus: P = 0.000; EcoRV locus: P = 0.033) and total solid (DA locus: P = 0.002; EcoRV locus: P = 0.015) in the Xinong Saanen dairy goat.