Genetic Variation of -Casein Gene Using AS-PCR and ARMS-PCR Techniques in Bovine Populations

Proteins in bovine milk are a common source of bioactive peptides. The peptides are released by the digestion of caseins and whey proteins. Therefore, the main aim of present study was to evaluation of the frequency of beta-casein variants of A1 (as bad peptide) and A2 (as beneficial peptide) and also, A and B alleles in Holstein and native breeds using both AS-PCR and ARMS techniques. Totally, 40 Holstein, 38Sarabi and 13 Gaja breeds were tested. In AS-PCR, three genotypes as A1A1, A1A2, and A2A2 were detected and frequencies of A1 allele of -casein were calculated as 52.5, 51.31 and 50% in Holstein, Sarabi and Gaja breeds, respectively. Frequencies of heterozygote genotypes A1A2 were observed as 90, 71 and 100% in Holstein, Sarabi and Gaja breeds, in that order. Frequencies of A2A2 genotypes of -casein were calculated as 2.5, 13.157, and 0.00% in the three studied breeds respectively. In ARMS-PCR, two genotypes as AA, and AB were observed and BB genotype wasn't found. Frequencies of AA, and AB genotypes were as 80 and 20%, 94.73 and 5.26% and 100 and 0.00% in Holstein, Sarabi and Gaja populations, respectively. Subsequently, allele B frequencies were calculated as 3.38, 1.92, and 0.00% in order to these three breeds. Comparison of both techniques was showed that samples having A1A1 genotype in AS-PCR technique were as AB genotype in ARMS-PCR significantly (p 0.05). All of the identified alleles in both techniques weren't in Hardy-Weinberg equilibrium. Overall, results of our study were revealed that frequencies of bad peptides were more than good peptide in the three different populations.