Category: Science & Technology Key figures: Alec Jeffreys (inventor, University of Leicester), Robert Melias (first convict, UK), Tommie Lee Andrews (first US convict), Richard Buckland (first exoneree by DNA)
Summary
DNA fingerprinting — also called DNA profiling — was invented in September 1984 by Sir Alec Jeffreys, a geneticist at the University of Leicester, England. Using a technique known as Restriction Fragment Length Polymorphism (RFLP), Jeffreys discovered that certain hypervariable, highly repetitive regions of the DNA sequence differ substantially between individuals, enabling a person to be matched or excluded from a biological sample with high certainty. The invention was published in the journal Nature in 1985, and Jeffreys immediately recognized its forensic potential.
The technique’s power was first demonstrated in a criminal investigation in 1986. In Leicestershire, England, police were investigating the murders of two teenage girls — Lynda Mann (killed 1983) and Dawn Ashworth (killed 1986) — both raped near the village of Narborough. A local seventeen-year-old, Richard Buckland, had confessed to one of the murders, but when DNA from the crime scenes was compared with Buckland’s sample, it not only failed to match him — exonerating Buckland in what became the first criminal exoneration by DNA evidence — but showed that a single unknown individual had committed both crimes. Police then conducted a mass screening of more than 4,500 men in the area. Colin Pitchfork, who had persuaded a friend to provide a sample in his place, was caught when the deception came to light; Pitchfork’s own sample matched, and he was convicted of both murders on 2 January 1988, becoming the first person convicted of murder using DNA evidence.
The first conviction for any crime using DNA evidence came one month earlier. On 13 November 1987 a British court found Robert Melias guilty of rape after forensic scientists matched DNA extracted from semen on the victim’s clothing to a blood sample taken from Melias — a conviction recognized by Guinness World Records as the first criminal DNA conviction in history. In the same month, Tommie Lee Andrews of Orlando, Florida, was convicted of rape, becoming the first person in the United States convicted through DNA evidence.
Significance
The 1987 convictions marked the moment DNA fingerprinting crossed from scientific discovery into legal proof. Biological evidence from crime scenes could now link a suspect to a crime — or, with equal certainty, exclude an innocent person — with a discriminating power no prior forensic technology had approached. British and US courts accepted the technique as admissible evidence in the same calendar year, establishing the procedural framework that spread to jurisdictions worldwide.
In the decades after 1987, DNA profiling became the gold standard of forensic identification. The United Kingdom launched the world’s first national forensic DNA database in 1995; the United States followed with the CODIS system in 1998. DNA evidence overturned hundreds of wrongful convictions, fundamentally changed policing and prosecution practice, and found wide application in paternity testing, immigration disputes, and mass-disaster victim identification. The Innocence Project, founded in 1992, used DNA evidence to exonerate more than 375 wrongly convicted people in the US alone.
Sources
- DNA profiling — Wikipedia
- First use of DNA profiling in a criminal conviction — Guinness World Records
Related
- Supernova 1987A — another Science & Technology landmark of 1987.
- FDA Approves AZT (March 20, 1987) — a third Science & Technology breakthrough of 1987: the first antiretroviral drug for HIV/AIDS.
- Microsoft Windows 2.0 (December 9, 1987) — the other major Science & Technology milestone of 1987.
- Black Monday (October 19, 1987) — the defining economic event of the same year.
- INF Treaty (December 8, 1987) — the landmark arms-control agreement of 1987.
- Index of 1987 topics · Timeline