Genotypic profiling of A1 and A2 β-casein alleles in Punganur cattle using PCR-RFLP

Abstract

Milk is regarded as nature’s perfect food due to the presence of essential nutrients required for the growth and development of mammals. The consumption of milk with a specific β casein variant either A1 or A2 had a relationship with the risk of diseases has been identified. Considering the importance of β casein variants with the health significance, the present study was undertaken in Punganur cattle (N=175) by using PCR-RFLP with Dde I restriction enzyme that showed the distribution of A1A2 (121 bp, 86 bp, and 35 bp) in 5 animals, A2A2 (86 bp and 35 bp) in 170 animals with no evidence of A1A1 genotype. The genotypic frequency of the A1A2 heterozygous β-casein variant of exon7 of the CSN2 gene was 0.029, whereas, for the A2A2 homozygous β-casein variant was 0.971 and the A1A1 homozygous β-casein variant is absent in Punganur cattle. The A1 allelic frequency of exon7 of the CSN2 gene was 0.014, whereas, the A2 gene frequency is 0.986 in Punganur cattle. The study indicates that there is a minimum genetic variability in the tested population of the Punganur cattle breed suggesting less or lower level of crossbreeding activities with exotic animals.

Keywords

• Allelic frequency, A1 and A2 alleles, β-casein gene, Dde I, Genetic frequency, Punganur cattle, PCR-RFLP