Technical note: Detection of bovine kappa-casein variants A, B, C, and E by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP).

We used polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis to screen the most frequent variants (A, B, C, and E) found in the bovine kappa-casein gene. The PCR products (453 bp) were heat-denatured, loaded onto nondenaturing polyacrylamide gels, and silver-stained. Each variant yielded patterns clearly distinguishable from the others. Optimal conditions for the simultaneous detection of the four variants were 12% polyacrylamide gels (100:1 acrylamide:bis-acrylamide ratio) with 5% glycerol and a constant running temperature of 10 degrees C. Eight reference samples initially used for this purpose and 40 anonymous samples of different cattle breeds diagnosed by PCR-RFLP and PCR-SSCP showed no discrepancies between the two methods and confirmed previous results. Because it is cost-effective, sensitive, and fast, PCR-SSCP is strongly recommended to routinely screen kappa-casein variants for industrial purposes or in cattle selection schemes.