Science & Measurement Codexery

Polymerase chain reaction

PCR amplifies specific DNA sequences rapidly for study.

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The polymerase chain reaction (PCR) is a laboratory method that rapidly amplifies specific DNA sequences to enable detailed study.[1]

Quick Facts

Inventor
Kary Mullis
Year invented
1983
Field
Biochemistry, Molecular Biology
Nationality
American

Facts from the source article.

Key facts and history

PCR amplifies a specific region of a DNA strand through repeated cycles of temperature changes.[2][3] The first use of a thermostable enzyme in PCR was reported in 1988.[4] Applications include DNA cloning, gene manipulation, diagnosis of genetic disorders, and detection of pathogens.[5] Thermal cycling, a process where reagents undergo repeated temperature changes for DNA melting and enzyme-driven replication, is the basis for most PCR methods.[6]

Short single-strand DNA fragments called primers, which are complementary to the target region, along with a thermostable DNA polymerase, are the two main reagents used in PCR.[6] Taq polymerase, a heat-stable enzyme originally obtained from Thermus aquaticus, is employed in nearly all PCR applications.[7][8] Prior to Taq polymerase becoming available, each cycle required manual addition of DNA polymerase, making the process both laborious and expensive.[7][4] Genetic testing, research, analysis of ancient DNA, and identifying infectious agents all rely fundamentally on PCR.[2]

Biomedical research and forensic science now commonly use PCR as an essential technique.[2]

What the cited sources add

The Nobel Prize announcement states that the PCR technique was first presented in 1985 and can replicate an individual DNA segment several million times in a test tube.[9] The Thermo Fisher Scientific education page notes that PCR machines are also known as thermal cyclers or thermocyclers.[4] The University of Utah resource describes that DNA polymerase in a cell needs to start from a primer, and in PCR, human-engineered primers steer the polymerase to the desired target sequence.[8] The Genetic Science Learning Center states that the orientation of primers allows polymerase to extend them toward each other, creating the chain reaction.[8]

According to the same source, reversing the electric current in a Peltier device allows many modern thermal cyclers to both heat and cool the block.[10][4]

References

  1. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: "The Nobel Prize in Chemistry 1993", NobelPrize.org (we also read that source) en.wikipedia.org
  2. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: "Enzymatic amplification of beta-globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia", Science, December 1985, p. 1350–54; "Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase", Science, January 1988, p. 487–91 (we also read that source) en.wikipedia.org
  3. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: "Effective amplification of long targets from cloned inserts and human genomic DNA", Proceedings of the National Academy of Sciences of the United States of America, June 1994, p. 5695–99; "Robust quantification of polymerase chain reactions using global fitting", PLOS ONE, 2012 (original not read by us) en.wikipedia.org
  4. Thermo Fisher Scientific, "PCR Thermal Cyclers Education". facts only, no text reused. thermofisher.com
  5. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: Ninfa, "Fundamental Laboratory Approaches for Biochemistry and Biotechnology", Wiley, 2009, p. 408–10 (we also read that source) en.wikipedia.org
  6. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: Khehra, "Polymerase Chain Reaction (PCR)", StatPearls, 2025 (original not read by us) en.wikipedia.org
  7. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: Enners, "Determining Annealing Temperatures for Polymerase Chain Reaction", The American Biology Teacher, 2012, p. 256–60 (original not read by us) en.wikipedia.org
  8. "PCR", Genetic Science Learning Center, University of Utah. facts only, no text reused. learn.genetics.utah.edu
  9. "The Nobel Prize in Chemistry 1993", NobelPrize.org. facts only, no text reused. nobelprize.org
  10. Wikipedia, "Polymerase chain reaction" (CC BY-SA 4.0), which cites: Thermo Fisher Scientific, "PCR Thermal Cyclers Education" (we also read that source) en.wikipedia.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Polymerase chain reaction (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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