Decontaminating the polymerase chain reaction.

Template DNA, which was added to a modified polymerase chain reaction mixture to simulate contamination, was inactivated by restriction enzyme digestion. After inactivation of the restriction enzymes, additional template, buffer and Taq polymerase were added to the reaction and the polymerase chain reaction proceeded. Results are presented using several different restriction enzymes with four base recognition sequences. The limitations of the method are discussed to indicate the tactics to be used for other DNA sequences.