The use of DNA to identify individuals and also any genetic diseases, such as cystic fibrosis, to which they might be susceptible. In this technique, which was invented by Sir Alec Jeffreys (1950– ) in the mid 1980s, enzymes are used to break DNA gathered from a person into fragments; because each individual has a different DNA pattern or ‘fingerprint’, the results can be used in forensic science, with DNA from hair, blood, etc. being sufficient to identify criminals. The technique is also used to identify parentage and ancestry. The use of DNA testing has been greatly enhanced by the discovery of the polymerase chain reaction.