Jeffreys, Alec John (1950– )

English geneticist who discovered the DNA probes necessary for accurate genetic fingerprinting so that a murderer or rapist could be identified by, for example, traces of blood, tissue, or semen.

Jeffreys was born in Oxford. He was educated at Merton College, Oxford, where he graduated in 1972. He was European Molecular Biology Organization Research Fellow at the University of Amsterdam 1975–77. He then moved to the department of genetics at the University of Leicester, where he has remained throughout his career.