Comparative screening of single nucleotide polymorphisms in β-casein and κ-casein gene in different livestock breeds of India

Lakshya Veer Singh,S Jayakumar,Anurodh Sharma,Shishir Kumar Gupta,S.P Dixit,Neelam Gupta,S.C Gupta

doi:10.1016/j.mgene.2015.03.005

Abstract

sThe most polymorphic milk protein gene is β-casein; 13 protein variants are known in cattle. Milk protein genetic polymorphism has received considerable research interest in recent years because of possible associations between milk protein and economically important traits in livestock. The present study was undertaken to explore the genetic polymorphisms in exon 7 of β-casein and exon 4 of κ-casein genes in Arunachali yaks (Bos grunniens), Sahiwal (Bos indicus) cattle, malpura sheep (Ovis aries) and Gaddi goat (Capra hircus). Results of the study revealed presence of 11 SNP variants in all livestock species. Four SNPs were observed in Bos indicus; two SNPs in Bos grunniens; three SNPs in Ovis aries and three SNPs in Capra hircus. These variations are found to be synonymous in nature as these variations do not result in their corresponding amino acids. A total of five polymorphic sites have been described at the κ-casein (CSN3) locus in the Indian domestic Gaddi goat (Capra hircus) when compared with exotic goat (X60763) while sequence analysis of κ-casein gene in sheep showed three novel nucleotide changes in malpura sheep when compared with the exotic sheep (AY237637). These results highlight the importance of taking into consideration the CSN3 SNPs when performing selection for milk composition in dairy livestock breeds.

Highlights

Finding effective genetic markers for economically important traits in farm animals, especially those which allow for faster and more precise prediction of breeding values, has been a challenge in animal genetics for decades
This study aimed to identify the genetic polymorphism of β-casein and κ-casein genes in Sahiwal cattle, Arunachali yak, malpura sheep and Gaddi goat
Variations and gene specific polymorphisms in the various livestock species of β-casein gene were investigated based on automated DNA sequencing and single nucleotide polymorphism (SNPs) detection, which allowed the detection of novel allele as well as status of previously reported alleles

Summary

Introduction

Finding effective genetic markers for economically important traits in farm animals, especially those which allow for faster and more precise prediction of breeding values, has been a challenge in animal genetics for decades. Β-casein is a member of casein cluster and with 13 protein variants known; it is the most polymorphic milk protein gene. Four casein genes (CSN1S1, CSN2, CSN1S2 and CSN3, respectively) are located as a cluster on chromosome 6 in cattle, sheep, and goats (Ferretti et al, 1990; Hayes et al, 1993; Popescu et al, 1996). Polymorphism of casein genes have been well studied in cattle and goat (Caroli et al, 2009; Marletta et al, 2007; Rando et al, 2000) and the variants have been found to be associated with the composition and biological properties of milk (Martin et al, 2002; Vinesh et al, 2013)

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