A new undergraduate biochem. lab. exercise was developed in which students ext. DNA from their own buccal cells and employ allele-specific polymerase chain reaction to identify a single nucleotide polymorphism that is responsible for a normal variation in red color vision. This exercise has substantial educational merit in that the techniques presented are widely employed in industrial, academic, and government research institutions. The exercise is likely to be of great benefit to undergraduate chem. students, particularly those seeking careers in biochem., forensics, medicinal chem., medicine, and related fields.