HIGHLY EFFICIENT SUBTRACTIVE HYBRIDIZATIO N OF CDNA

A scheme for subtractive hybridization is described allowing for a 500 -1000 fold enrichment of low abundant cDNA. The scheme is based on the previously described principle of normalization of an initial mixture of differently represented cDNAs in the single-stranded portion of a tracer after the first round of subtraction [1] and the principle of a trapper [6] excluding the fraction of the double-stranded cDNAs forme d during the first round from the subsequent PCR-amplification. The te chnique is simple and makes unnecessary the separation of the tracer, driver and hydrids formed after the subtraction.