SUBTRACTIVE HYBRIDIZATION - THEORETICAL-A NALYSIS AND A PRINCIPLE OF THE TRAPPER

An analysis of the kinetics of the subtractive hybridization and the e xtent of enrichment of sequence differences between two otherwise iden tical genomes or transcripts has been carried out for different condit ions. The hybridization of single- or double-stranded DNA (tracer) con taining the difference (target) to the large excess of single-stranded complementary DNA not having the sequence (driver) gives a much highe r enrichment of the target than hybridization of double-stranded drive r and tracer or double-stranded driver with single-stranded tracer. Th e conclusion is that the first approach can give means for efficient e xtraction of the target without artificial simplifications of the geno mes before subtraction. A principle of the <<trapper>>, preventing the hybrids formed from dissociation in the course of PCR amplification o f the target enriched, is proposed as a complement to the single-stran ded DNA hybridization in the process of highly efficient subtraction.