A technique for screening a population for a specific point mutation that uses fluorophore-labelled PCR primers. Three primers are designed for amplification of a restriction fragment that contains the mutation site near one end: the primer for the end distal to the mutation site is unlabelled; two primers for the other end containing the normal and the mutant sequence are each labelled with a different and distinguishable fluorophore, e.g. the normal with a red-fluorescing group and the mutant with a green-fluorescing group. When the restriction fragment is amplified in the presence of the primers, and the product separated from excess unincorporated primers, the amplified products will fluoresce red if from a normal subject, green if from a homozygous affected individual, and yellow if from a heterozygous individual.