CONFORMATION SENSITIVE GEL-ELECTROPHORESIS FOR SIMPLE AND ACCURATE DETECTION OF MUTATIONS - COMPARISON WITH DENATURING GRADIENT GEL-ELECTROPHORESIS AND NUCLEOTIDE SEQUENCING

Previously, an assay called conformation sensitive gel electrophoresis (CSGE) was developed for sampling PCR products for the presence of si ngle-base and larger base mismatches in DNA. The assay was based on th e assumption that mildly denaturing solvents in an appropriate buffer can accentuate the conformational changes produced by single-base mism atches in double-stranded DNA and thereby increase the differential mi gration in electrophoretic gels of heteroduplexes and homoduplexes. He re the sensitivity of assays by CSGE was improved by limiting the maxi mal size of the PCR products to 450 bp and making several changes in t he conditions for PAGE. With the improved conditions, CSGE detected al l 76 previously identified single-base changes in a large series of PC R products from collagen genes that contain multiple exons with highly repetitive and GC-rich sequences. In a survey of 736 alleles of colla gen genes, CSGE detected 223 unique single-base mismatches that were c onfirmed by nucleotide sequencing. CSGE has the advantage over other m ethods for scanning PCR products in that it is simple, requires no spe cial preparation of PCR products, has a large capacity, and does not u se radioactivity.