Identification of Polymorphisms of Gene CSN2 of B Casein in Greek Cow Breeds (Holstein) by Restriction Fragment Length Polymorphism

The research focused to detect and identify genetic polymorphisms in exon 7 of the β-casein CSN2 gene in blood samples from Greek Holstein cows. For this purpose, DNA was extracted from 120 blood samples of cows. The desired region of exon 7 was amplified by PCR, resulting in a 121 bp product. The PCR product was digested by restriction fragment length polymorphism (RFLP) method. The results suggest that the A1A2 genotype prevails over the others. Specifically, of the 120 cattle, 72 showed triple bands of 121 bp, 86 bp, and 35 bp indicating the A1A2 genotype. The 42 cattle showed a single band at 121 bp, indicating that they carried the A1A1 genotype. The remaining 6 showed only two bands of 86 and 35 bps, indicating that they carried the A2A2 genotype. In the total population of heterozygotes A1A2-0.60 were the most frequent, while homozygotes A2A2-0.06 were the least frequent ones. This suggests a slight superiority of allele A-0.65.