Identification of novel single-nucleotide polymorphism at exon1 and 2 region of B4GALT1 gene and its association with milk production traits in crossbred cattle of Kerala, India.

Beta 1,4-galactosyltransferase-I gene (B4GALT1) is an important candidate gene for milk performance traits, encodes catalytic part of lactose synthesis. Main objectives of present study is identification of single-nucleotide polymorphism in exon 1 and 2 region of B4GALT1 and to find significant association of genetic variants with milk performance traits in crossbred cattle of Kerala. The study was conducted on two hundred crossbred cattle maintained at various farms of Kerala Veterinary and Animal Sciences University, India. Genomic DNA was isolated and polymorphism of gene were detected by Single Strand Confirmation Polymorphism. Genotype and allelic frequency were estimated. Chi-square analysis revealed that screened population is under Hardy Weinberg equilibrium. Nucleotide sequence analysis revealed a novel non-synonymous single-nucleotide variation (T94A) in exon 1 and a non-synonymous mutation of T97C in exon 2 of B4GALT1 gene in the screened cattle population. Association analysis of genetic variants was done with milk production traits and major non-genetic factors using fixed models. Different genetic variants of B4GALT1 was significantly associated with 305 days milk yield, lactose, protein percent. Study indicates existence of genetic variability in B4GALT1 gene on crossbred cattle of Kerala and suggests a scope of considering genetic variants of B4GALT1in selection strategies.