Figure 2.

PCR–CRMS assay with self-annealed PCR products (mutation detection mode). A PCR product, either heterozygous (left, top) or homozygous (right, top), is heat denatured and reannealed to itself. The heterozygous sample is expected to generate equal amounts of homoduplex (PM) and heteroduplex (MM). However, the homozygous sample generates only one homoduplex (PM) molecule. MM duplexes are specific targets for activated MutH. Following MutHLS treatment 50% of the heterozygous sample was digested; only a 5% background level of cleavage was observed with the homozygous sample.