Complete mutation detection using unlabeled chemical cleavage.

We have developed a strategy for the complete detection of point mutations, small insertions and deletions by chemical cleavage based on the methodology of Cotton et al. (1988). The technique was extended by the development of a nonisotopic cleavage product detection system using silver staining after gel electrophoresis. The complete mutation detection was achieved by use of mutant and wild-type DNAs in equimolar quantities in duplex formation, thus any mismatches that are resistant to chemical cleavage (e.g., some T.G mismatches) are easily detected by cleavage of the complementary heteroduplex (e.g., A.C mismatch). With such a strategy mutant DNAs can be screened for mutations and polymorphisms. The advantages of complete unlabeled mutation detection are considerable.