This technique utilizes an enzyme resolvase, endo vii, cloned from the bacteriophage t4. This enzyme has high specificity to find deletions, insertions, and base substitutions mutations or any mismatches. First the pcr is utilized to intensify the normal and mutant allele of targeted sequence, these pcr primers are labeled with fam(6-carboxyfluoroscein amidite) which is a blue fluorescent dye and reverse primer with tet(4,7,2,7-tetra chloro-6-carboxy fluoroscein) amidite which is a green fluorescent dye.

Denaturation and renaturation of normal and mutant allele in a mixture is made, consequently mismatch heteroduplexes will form about 50 % of the time, each and every base pair creates two mismatch. The endo vii enzymes then scan the double stranded dna until it finds structural distortion, either a bubble made by single base pair mutations or a hetero duplex loop created by hybridization of a wild type allele with a mutant allele having an insertion or deletion. The enzyme cleaves with in 6 base pair on 3"side of mutation creating two smaller fragments, one blue and the other one green. The dna sequence is analyzed on automated dna sequence and mobility of every fragment is analyzed.