What does the acronym PCR stand for?

The acronym PCR stands for Polymerase Chain Reaction. PCR is a popular lab technique that is used to make multiple copies of a particular segment of DNA in vitro (inside a test tube instead of an organism). It was developed by Kary Mullis in 1983. PCR occurs in 3 stages. These stages are denaturation stage, annealing stage, and elongation (extension) stage.

The denaturation stage is the first stage. At this stage, the temperature is increased to about 92 degrees Celsius. The heat helps break hydrogen bonds between DNA strands. In the annealing stage, the temperature is reduced to 55 to 65 degrees Celsius to allow primers to bind the complementary sequence on template DNA. In the last stage, the temperature is raised again to 72 degrees Celsius to allow the synthesis of new DNA strands.