Fig. 5.

The discovery of an SNP in the TNF promoter region by two methods: resequencing (a) and photocleavage (b) with Rhchrysi. In a, the TNF promoter was sequenced by using a pooled genomic DNA sample. A portion of these sequencing data is shown highlighting a polymorphic site, demonstrating C allele frequency of 89% with a minor A allele frequency of 11%. In b, with our targeting assay, this SNP is readily detected by capillary electrophoresis. After photocleavage with 500 nM Rhchrysi at 442 nm for 10 min, the parent band, 377 bases in length, is cleaved and a new peak appears at 105 bases. This fragment length corresponds exactly with the location of the SNP detected by sequencing in a.