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Glossary Term
Glossary Term PCR
Definition Polymerase Chain Reaction. A method of amplifying specific DNA segments based on hybridization to a primer pair. A DNA sample is denatured by heating in the presence of a vast molar excess of short single-stranded DNA primers (around 20 nucleotides) whose sequence is chosen based on the target sequence. The reaction mixture also contains a thermostable DNA polymerase, dNTPs, and buffer. The primer sequences are selected so that they:
  1. are derived from opposite strands of the target sequence,
  2. have their 3' ends facing each other, and
  3. are separated by a length of DNA that can be reliably synthesized in vitro.
The sample is then cooled to a temperature that allows primer annealing and in vitro replication. The sample is subjected to multiple cycles of denaturation and cooling to allow multiple rounds of replication. The quantity of the target sequence doubles during each cycle, causing the target sequence to be amplified, while other DNA sequences in the sample remain unamplified. See the Figure at Access Excellence.

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last database update
07/23/2014
MGI 5.19
The Jackson Laboratory