Chemical and Biomolecular Engineering, Department of


PCR: Replicating success

Date of this Version



This article was published in Nature 435, 235-238 (12 May 2005) | doi: 10.1038/435235a Visit Nature for the full article


PCR often gets taken for granted, but there are ways of making it faster, more accurate and easier to perform. Pete Moore investigates. As a means of rapidly copying a selected template sequence from a DNA mixture in vitro, PCR by itself and in combination with other techniques has found a vast range of applications. These range from sequence detection and isolation for research, forensics and species identification to detecting mutations and polymorphisms and amplifying RNA-derived cDNAs for microarray analysis of gene expression. As well as standard PCR, the technique now comes in the form of real-time quantitative PCR (real-time PCR or qPCR). This uses fluorescent probes to monitor the amount of product at the end of each cycle, and real-time PCR machines look for the cycle at which they can first detect fluorescence. This relates to the number of copies of original template — the greater the number of starting copies, the fewer cycles are needed to reach fluorescence detection.