Genotyping results for the CHRNA3 SNP of six DNA samples. Allelic discrimination assay using DNA extracted from whole urine stored at −20°C for 6 months. The assay was performed in duplicate. Fluorescence for the wild-type allele is plotted along the y-axis (the dye is “FAM”) and for the mutated allele, labeled with the dye “VIC”, along the x-axis. WT, Samples homozygous for the wild-type allele; MUT, samples homozygous for the mutated allele; HET, samples heterozygous (wild-type alleles+mutated allele); ×, “no template” controls.