Figure 4.

(A and B) Gel electrophoretogram of PCR products of the GST M1 gene (A) and PCR and restriction fragment-length polymorphism analysis of the 1245C→G polymorphism of the hOGG1 gene (B). The sizes of the DNA fragments of GST M1 gene amplified by PCR were 268 and 215 bp, respectively (lanes 1 through 3), but only 268 bp is amplified from total DNA of the patients with the GST M1(−) genotype (lanes 4 through 6). The C→G substitution at nucleotide 1245 of the hOGG1 gene creates a recognition sequence for Fnu4H I, which digests the 200-bp fragment into two 100-bp fragments. Lanes 7 and 8 are wild type (CC), lanes 9 and 10 are heterozygotes (CG), and lanes 11 and 12 are homozygotes (GG) for the hOGG1 1245C→G polymorphism. M, DNA size marker; N, negative control.