Relationship between Kappa-Casein gene polymorphism with milk economic traits in native cattle of Guilan province

In this research, the relationship between polymorphism of CSN (Kappa-Casein) gene and production traits in Guilan native cattle was studied. Blood samples were taken from 100 cows Fouman, Rasht and Astaneh-ye-Ashrafiyeh. Genomic DNA was extracted by modified salting out method. A 350 bp fragment of the bovine kappa-CSN gene was amplified by Polymerase Chain Reaction (PCR) using a specific primer. The PCR products were digested by Hinf I to determine kappa-casein genotypes with PCR-RFLP marker. Observed frequencies for genotypes AA, AB, BB were 0.48, 0.52, 0.00 and allelic frequencies for A and B were 0.74 and 0.26, respectively. The chi-square test results showed that the studied population were not at Hardy-Weinberg equilibrium. Comparison of least square means indicated that the polymorphism has a significant effect on milk yield, fat and protein percentage (P