Professor Sir Alec Jeffreys (born 1950), English molecular biologist and discoverer of DNA fingerprinting. He is holding up autoradiograms of DNA fingerprints. Professor Jeffreys developed the technique of DNA fingerprinting in 1984 at the Department of Genetics at the University of Leicester. A DNA fingerprint is a unique genetic sequence that identifies any individual, human or animal, from a tiny sample of tissue such as blood, hair, or sperm. Its many uses include the identification and conviction of criminals, and the proving of family relationships, such as the paternity of a child. Only 'identical' twins share the same DNA. Photographed in March 2004.