Detection of a novel CYP1A2 polymorphism. (Left) Analysis of PCR-extended fragments from exon 2 of CYP1A2. Lanes 1 and 2 [without (\-) and with (+) MboII digestion] are from a sample of homozygous C2866. Lanes 3 and 4 [without (\-) and with (+) MboII digestion)] are from a sample of heterozygous C/G2866. (Right) Sequencing gel of the PCR product containing heterozygous C/G2866 in exon 2. See the article in this issue by Huang et al. on page 98 for further details.