Sir Alec John Jeffreys, (born 9 January 1950) is a British geneticist, who developed techniques for genetic fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes. He is a professor of genetics at the University of Leicester, and he became an honorary freeman of the City of Leicester on 26 November 1992. In 1994, he was knighted for services to genetics.
Jeffreys was born into a middle-class family in Oxford, where he spent the first six years of his life until 1956 when the family moved to Luton, Bedfordshire.
He attributes his curiosity and inventiveness to having been gained from his father, as well as his paternal grandfather, who held a number of patents. When he was eight, his father gave him a chemistry set, which he enhanced over the next few years with extra chemicals, even including a small bottle of sulphuric acid.
After finishing his doctorate, he moved to the University of Amsterdam, where he worked on mammalian genes as a research fellow, and then to the University of Leicester in 1977, wherein 1984 he discovered a method of showing variations between individuals' DNA, inventing and developing genetic fingerprinting.
Jeffreys says he had a "eureka moment" in his lab in Leicester after looking at the X-ray film image of a DNA experiment on 10 September 1984, which unexpectedly showed both similarities and differences between the DNA of different members of his technician's family.
Within about half an hour, he continued, he realized the possible scope of DNA fingerprinting, which uses variations in the genetic code to identify individuals. The method has become important in forensic science to assist police detective work, and it has also proved useful in resolving paternity and immigration disputes.
The method can also be applied to non-human species, for example in wildlife population genetics studies. Before his methods were commercialized in 1987, his laboratory was the only center in the world that carried out DNA fingerprinting, and was consequently very busy, receiving inquiries from all over the globe.
According to en.wikipedia