Analysis of p53 C309T, prothrombin 20210 G-to-A, and MTHFR C677T polymorphous sites in homo- and heterozygous DNA by the DSNP assay. (A) Photographs obtained on the fluorescent stereomicroscope equipped with green (G) and red (R) filters. GR, computer superposition of images obtained with green and red filters. n/n, homozygous DNA samples comprising wild-type sequence variant; n/m, heterozygous DNA samples; m/m, homozygous DNA samples comprising mutant sequence variant. (B) Normalized emission spectra of these samples obtained on a spectrofluorometer, with excitation at 480 nm (for green fluorescence) and 550 nm (for red fluorescence). Fluorescence values, ΔF, were normalized as described in Table 1. Green line, homozygous DNA samples comprising the wild-type sequence variant; red line, homozygous DNA samples comprising the mutant sequence; blue line, heterozygous DNA samples.