Effect of Osteopontin gene variants on milk production traits in Holstein Friesian crossbred cattle of Kerala

Abstract

Osteopontin gene (OPN) is located in the quantitative trait loci (QTL) for milk production traits in bovine chromosome 6.In the present study the impact of cytosine to thymine transition in the intron-4 of OPN gene (g.8514C > T) on milk production traitswas analysed in the Holstein Friesian crossbred cattle of Kerala. Genomic DNA was isolated and a fragment of 290 bp enclosing thepolymorphic site was amplified and genotyped by restriction fragment length polymorphism (RFLP) using endonuclease, BSeN1. Thegenetic variants were distributed according to Hardy-Weinberg equilibrium. The T allele was found to be the major one (T/0.76, C/0.24)and the genotype frequencies were TT/0.60, CT/0.32, and CC/0.08. The amplicons of genotypes were sequenced by sangers dideoxytermination technique and confirmed the mutation. Association study using the General Linear Model-Analysis of Variance (GLMANOVA) considering marker, season of calving, parity and herd as fixed factors and dairy trait as dependent variable revealed that noneof the yield traits (305 day milk yield, peak yield, fat yield, protein yield, solids not fat yield, lactose yield, daily milk yield) or compositiontraits (fat percent, protein percent, solids not fat percent and lactose percent) of milk production analysed were significantly differedbetween CT and TT genotyped animals. The OPN gene polymorphism (g.8514C > T) can be suggested for marker assisted selection(MAS) for future breeding programmes for dairy cattle only after extensive association studies.