Polymorphisms of the β-1,4 galactosyltransferase-I gene in Holsteins

Prl and B4GALT-1 gene polymorphism and their association with milk production traits in crossbred cattle of Kerala

The main objective of present study was to explore the genetic variation in exon 3 of PRL (185 bp) and exon-2 of B4GALT-1 (256 bp) locus and analyze their associations with milk production traits. The study was conducted on 200 crossbred cattle distributed in different farms under Kerala Veterinary and Animal Sciences University and field centres of ICAR-FPT scheme, Mannuthy. Polymorphism of both the genes was detected by Single Strand Confirmation Polymorphism (PCR-SSCP). Similar banding pattern were noticed in exon-3 region of PRL, population was found to be monomorphic, indicating conserved nature of this fragment in the screened crossbred cattle population of Kerala. Two unique band patterns were detected in 256 bp fragment of B4GALT-1. Sequencing revealed a nonsynonymous single nucleotide variation in c.521T>C in exon 2 of B4GALT-1, resulted in an amino acid substitution of methionine to threonine due to a codon change of ATG to ACG. Different genetic variants of B4GALT-1 was significantly associated with 305 days milk yield and protein percent. The study indicates the existence of genetic variability in B4GALT-1 gene on crossbred cattle population of Kerala and suggests a scope of considering genetic variants of B4GALT-1 gene in selection of cattle for higher milk production.

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.