Polymerase chain reaction
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The polymerase chain reaction, or PCR, is a laboratory method used to make many copies of a selected DNA region. Repeated temperature cycles allow a small initial quantity of DNA to be amplified until it can be detected or analysed.
Each cycle normally has three stages. Denaturation separates the DNA strands, annealing allows short primers to bind to complementary sequences, and extension allows a heat-stable DNA polymerase to synthesise new strands.
Because newly produced DNA becomes a template in the next cycle, the amount of target material can increase approximately exponentially during the efficient phase of the reaction. Primer design, temperature, reagents, contamination control, and template quality strongly affect the result.
PCR is used in medical diagnostics, genetics, evolutionary research, forensic science, environmental monitoring, cloning, and sequencing workflows. Variants include reverse-transcription PCR for RNA, quantitative PCR for estimating abundance, and digital PCR for highly precise counting.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Polymerase_chain_reaction