Use of a single-strand conformation polymorphism analysis to perform a simple genotyping of bovine kappa-casein A and B variants.

We propose an alternative method for casein genotyping, generally carried out using polymerase chain reaction followed by restriction fragment length polymorphism analysis. Application of the single-strand conformation polymorphism technique detects nucleotide changes in the fragment amplified by means of polymerase chain reaction and thus avoids the 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 conformation polymorphism analysis of heat denatured fragments in acrylamide-bis-acrylamide (100:1) gels followed by silver staining. kappa-Casein genotyping is therefore simplified, although variants A and E on the one hand, and B and C on the other, are not distinguishable with this technique.