Association between alphas1-, beta- and kappa-casein loci in two Italian cattle breeds

The genetic polymorphism alphas1-, beta- and kappa-caseins was examined by gel electrophoresis in two Italian breeds, Valdostana and Piedmont. The results obtained from acid and basic migration show that the gene frequencies of the two breeds are very similar. Non independent assortment of genotypes among these milk protein loci was also studied. Results of analyses carried out on loci pairs showed that the genetic complex alphas1-CnB - beta-CnA2 was the most common in both breeds. In addition, the measure of linkage disequilibrium or gametic association (denoted delta) showed a close association between alphas1-Cn and beta-Cn, and between beta-Cn and kappa-Cn. No significant association was found between alphas1-Cn and kappa-Cn. This is in line with the model proposed by Grosclaude et al. (1973).