Abstract: A process for producing a particular nucleic acid sequence from a given sequence of DNA or RNA in amounts which are large compared to the amount initially present, using PNAs in conjunction with the polymerase chain reaction (PCR) is disclosed. The process may be used to amplify relatively long DNA or RNA sequences of about 600 base pairs or longer, while reducing the generation of anomalous products and the tendency to preferentially amplify smaller nucleic acid (DNA or RNA) fragments when present in the heterozygous state with a larger allele.