Studying exon 4 of kappa-casein gene in Kermani sheep using PCR-RFLP

Kappa casein plays an essential role in the case of micelle stabilization and their size and the specific biological function. Hence, the purpose of this study was to investigate polymorphism in the exon 4 gene of CSN3 using the PCR-RFLP technique. For this purpose, blood samples were taken from 150 Kermani sheep, and genomic DNA was extracted. The polymerase chain reaction (PCR) was performed a pair of specific primer. PCR productions were separated using agarose gel. The amplified fragment was digested with HaeIII enzyme and determining the genotype was performed. The results of this study led to the identification of two genotypes that allele frequencies were estimated by Popgene software. Allele frequency of A and B alleles for CSN3 gene was respectively 70% and 30% for the Kermani sheep population. Chi-square test showed that studied population is not in Hardy-Weinberg equilibrium (P≤0.05). Number of observed allele, number of effective allele, observed heterozygosity, expected heterozygosity, Nei’s index, mean of heterozygosity and Shanon’s index were obtained 2, 1.72, 0.60, 0.43, 0.42, 0.42 and 0.61 respectively. In conclusion, it can be concluded that studied Kermani sheep population has a high degree of genetic variability. Therefore, next studies on these animals, especially on native animals should aim to determine crucial relationship between kappa casein genotypes and maternal characteristics, as selection could be enhanced by the inclusion of genetic markers in breeding decisions.