DIRECT CLONING OF UNMODIFIED PCR PRODUCTS BY EXPLOITING AN ENGINEEREDRESTRICTION SITE

A method is described for the direct cloning of DNA fragments amplifie d by the polymerase chain reaction (PCR). An oligodeoxyribonucleotide, bearing two engineered XcmI sites placed in tandem, was used to gener ate cloning vectors bearing single 3' deoxythymidine (dT) overhangs at their ends. These 3' dT overhangs are compatible with the 3' deoxyade nosine overhangs found on most Tag polymerase-amplified PCR products. Consequently, Taq polymerase-amplified PCR products can be ligated dir ectly into these modified restriction sites.