is a way to cyclically amplify portions of DNAs that match certain primer(s). It was developed in 1983 by Kary Mullis. PCR is now a common and important technique used in medical and biological research labs for a variety of applications. Amplification is achieved by cycling the following three steps:

# Denaturation: Heat mixture containing DNA to 95 °C so the twos strands become separate from each other.
# Annealing: Cool the mixture to 50–65 °C