Genotyping of HF Crossbred Breeding Bulls for A1/A2 Variant of β-Casein Gene

Abstract

Background: The variants of β-casein (CSN 2) gene viz. A1 and A2 are supposed to be related with human health. Hence, to know the status of breeding bulls used for AI services were screened for A1 and A2 variants. Total 47 blood samples of crossbred breeding bulls from Frozen Semen Laboratory, Pune and Aurangabad were used for present work. Methods: The extraction of genomic DNA by phenol-chloroform method were carried out from the blood samples of 47 breeding bulls. Further, DNA based PCR-RFLP method was used to identify the A1, A2 variants. Pure DNA fragments of b-casein (CSN 2) gene were amplified by PCR using suitable pairs of primer to amplify 121 bp and 244 bp products. The primer used to amplify 244 bp was allele specific. The 121 bp fragment then subjected to restriction enzyme digestion. The restriction enzyme digestions resulted into two types of band pattern. The 244 bp fragment was used for validation of A1 and A2 allele of 121 bp. Result: Two types of genotypes i.e. A1A2 and A2A2 were revealed in the experimental population of HF crossbred breeding bulls. The genotypic frequency of A1A2 and A2A2 was estimated 65 and 35 per cent, respectively. The present frequency status of A1 and A2 allele in the breeding bulls may be suggested for planning future breeding strategy in dairy cattle.