1984 – DNA fingerprinting discovered

Alec Jeffreys"My life changed on Monday morning at 9.05 am, 10 September 1984,” recalled Professor Sir Alec Jeffreys with commendable precision. “What emerged was the world's first genetic fingerprint. In science it is unusual to have such a 'eureka' moment.”

Alec Jeffreys joined the University of Leicester’s Department of Genetics in 1977, where he directed his research towards variability in human DNA. His ‘eureka moment’ seven years later was the realisation that a human DNA could produce consistent, unique patterns and that these could be used to not only identify individuals but also indicate familial relationships.

The first legal case to use this new technique was an immigration case which hinged on proving whether a woman and a young boy were mother/son or aunt/nephew. A paternity case followed shortly after and for two years Jeffreys’ university lab in Leicester was the only place in the world offering this service.

It was a double murder case in 1986 which made the public – and police forces – aware of the forensic capabilities of ‘DNA fingerprinting’. Two young woman had been raped and murdered in Leicestershire; a suspect confessed to one murder but not the other and the local force called on Jeffreys to prove he was guilty of both. Instead the DNA evidence proved he was a fantastist, guilty of neither murder. A mass collection of blood samples from all local adult males was then arranged and, when Colin Pitchfork was overheard boasting of how he had avoided this by switching samples, the police were informed. Pitchfork was subsequently convicted of both murders.

DNA fingerprintThe potential applications of the technology developed by Sir Alec have extended well beyond the obvious criminal and paternity cases. In 1992 he was called on to determine whether a body exhumed in Brazil a few years earlier was, as claimed, that of Nazi war criminal Josef Mengele (it was). Shortly after, he was approached by the BBC to appear on Jim’ll Fix It, helping similar-looking twin girls know for definite whether they were identical (they were).

Until his retirement in 2012, Professor Jeffreys continued to teach each new cohort of Genetics undergraduates as well as progressing his research. In 2010 the discovery of DNA fingerprinting was named ‘the second most important discovery in the history of UK scientific research’ in a poll of academics.