Polymerase chain reaction (PCR)
- Polymerase chain reaction, or PCR, is a technique to make many copies of a specific DNA region in vitro (in a test tube rather than an organism).
- PCR relies on a thermostable DNA polymerase, Taq polymerase, and requires DNA primers designed specifically for the DNA region of interest.
- In PCR, the reaction is repeatedly cycled through a series of temperature changes, which allow many copies of the target region to be produced.
- PCR has many research and practical applications. It is routinely used in DNA cloning, medical diagnostics, and forensic analysis of DNA.
What is PCR?
The steps of PCR
- Denaturation (): Heat the reaction strongly to separate, or denature, the DNA strands. This provides single-stranded template for the next step.
- Annealing ( ): Cool the reaction so the primers can bind to their complementary sequences on the single-stranded template DNA.
- Extension (): Raise the reaction temperatures so Taq polymerase extends the primers, synthesizing new strands of DNA.