Analysis of beta-casein gene (CSN2) polymorphism in Tharparkar and Frieswal cattle

A1 and A2 are most frequently observed Beta-Casein variants in dairy cattle. A1 β-casein on digestion releases an opioid, BCM-7 which has been found significantly associated with type 1 diabetes mellitus (DM-1), ischemic heart disease (IHD), autism and including other immune suppression activities in man. Whereas A2 β-casein is devoid of such adverse effects. The present study involved genotyping of 181 cattle of two breeds viz., Tharparkar and Frieswal for genetic variants A1 and A2 beta casein gene by PCR-RFLP method using DdeI restriction enzyme. The results showed that the A1 and A2 allelic frequency as 0.04 and 0.96 in Tharparkar while in Frieswal (HF × Sahiwal), it was 0.37 and 0.63 respectively. The average genetic diversity (0.47), polymorphism information content (0.35) and effective allele number (1.87) reflected existence of medium genetic variability in tested population. The lower PIC value in Tharparkar cattle (0.073) indicates low genetic diversity whereas; moderate vale (0.35) in Frieswal cattle indicates medium genetic diversity. Higher fixation index value revealed that random mating is being practiced in both populations.