Polymerase chain reaction (PCR) is a method used widely in molecular biology to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to take a very small sample of DNA and amplify it to a large enough amount to study in detail.
Invented in 1983 by Kary Mullis, who won the Nobel Prize in Chemistry for his discovery.
A cornerstone of modern molecular biology, used in a vast array of applications, from forensic science to genetic testing.