What Is a PCR Primer?

A PCR primer, or polymerase chain reaction primer, is a short segment of DNA that researchers use to amplify, or replicate, a targeted portion of the DNA molecule. This results in billions of copies of the targeted area of DNA that enable scientists to conduct important research.

Prior to the PCR process, researchers had been unable to obtain sufficient quantities of DNA samples to conduct meaningful research. Using PCR, the DNA molecule is split into smaller segments called sequences. A PCR primer is specifically designed and produced in a laboratory to be the molecular complement to the targeted sequence. The primer determines which portion of sequence will be replicated and works with other enzymes to initiate a chain reaction that produces billions of copies of this sequence. Each targeted sequence requires a specifically designed primer.