Polymorphism of κ-Casein Gene in Iranian Holsteins

Background: Genetic polymorphism of milk proteins has been associated with composition, manufacture, and traits of milk. Caseins are the most important milk proteins whose genes are strongly linked and inherited as a raceme. κ-casein which is a quantitatively minor constituent of bovine milk is thought to play a critical role in organization, fixation and aggregation of casein micelles and firmness of curd during cheese making. Objectives: In this study, we considered polymorphism of κ-casein gene in Iranian Holstein cows. Materials and Method: In this study, κ-casein gene polymorphism among 50 DNA samples of Iranian Holstein cows via Polymerase Chain Reaction sequence analysis (PCR-Sequencing) was considered. For data analysis SPSS 11.5 (ANOVA test) was used. Results: Four polymorphic sites that created 4 variants and seven different genotypes of κ-casein gene were identified. In this population the frequencies of A, B, C, and E alleles were estimated as 0.391, 0.413, 0.087, and 0.109 respectively. Conclusion: We suggested that the B allele of κ-casein gene frequency should be increased in Iranian Holsteins because it has an essential factor in marker-assisted selection for milk traits.