Abstract:
Milk contains a protein called kappa-casein, which controls the function and size of milk micelles as well as their ability to form and stabilize. Kappa-Casein gene (CSN3) polymorphisms were investigated in 70 Domestic (Native and Meriz goat) and Wild goat using the PCR-RFLP method and direct sequencing. CSN3-Hea III/RFLP revealed two homozygous genotypes AA and BB. For the AA and BB genotypes, the computed genotype frequencies were (0.87) and (0.13), respectively. The allelic frequency was 0.87 for the A allele and 0.13 for the B allele. The sequence data of CSN3 gene of Meriz and Wild goats revealed 2 SNPs in functional region, one SNP of Wild (ACC. No: OR050625.1), and one in Meriz goat (ACC. No: OR050626.1). In position 415 in Wild goat, the amino acid Methionine changed to Isoleucine by changing (ATG) to (ATA). On the other hand, the point mutation in Meriz goat at the positions 449 led to change amino acid Valine to Isoleucine by alternation (GTC) to (ATC). The PCR-RFLP and SNP analysis is a powerful tool for the genetic study of CSN3 variability in domestic and wild goats, allowing both the simultaneous identification of different alleles, and the detection of new variants. Establishing relationships between genotypes and both quantitative and qualitative milk qualities will require additional investigation.