USE OF A SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS TO PERFORM A SIMPLE GENOTYPING OF BOVINE KAPPA-CASEIN A-VARIANT AND B-VARIANT

We propose an alternative method for casein genotyping, generally carr ied out using polymerase chain reaction followed by restriction fragme nt length polymorphism analysis. Application of the single-strand conf ormation polymorphism technique detects nucleotide changes in the frag ment amplified by means of polymerase chain reaction and thus avoids t he use of restriction enzymes. A 453 bp fragment from exon IV of kappa -casein has been amplified. The two variants (A and B), found with the highest frequencies in most bovine breeds and included in some dairy cattle selection schemes, can be discriminated using single-strand con formation polymorphism analysis of heat denatured fragments in acrylam ide-bis-acrylamide (100:1) gels followed by silver staining. kappa-Cas ein genotyping is therefore simplified, although variants A and E on t he one hand, and B and C on the other, are not distinguishable with th is technique.