Polymerase chain reaction

Polymerase chain reaction (PCR) is a way to make many copies of a sequence of DNA (this is sometimes called 'amplifying' the DNA). It is done in a lab, using an enzyme called DNA polymerase. It is called chain reaction because the result of one cycle is used immediately for the next cycle. This allows exponential growth to happen.

PCR has many uses in a biological or biochemical setting. Because DNA is unique for every living thing, experimenters can often extract only small amounts of the DNA they are interested in from a specimen. These amounts are usually too little to be useful, and so a scientist will use PCR to make enough copies to start experimenting with. For this reason, it is one of the most common techniques used in genetics labs around the world, making it useful in experiments on many things, including gene therapy, infectious diseases, and even forensics.

This process was developed in 1983 by Kary Mullis. He was not the first person to develop the PCR process, but he was the first to make the process usable. He was awarded the Nobel Prize in Chemistry for his work in the PCR process. It was a joint award, the other scientist being Michael Smith, who worked on a related project.