Forty Years of the Genetic Fingerprint
Four decades ago, a technique discovered by accident in a Leicester laboratory was used to solve a murder — and, in the same case, to free the wrong man.
Today, 42 years ago…
Four decades ago, a technique discovered by accident in a Leicester laboratory was used to solve a murder — and, in the same case, to free the wrong man.
The accident
Alec Jeffreys was developing X-ray film in his lab at the University of Leicester, studying inherited variation in a gene. What appeared was a pattern of bands, different for every individual but inherited traceably through families.
He later said the significance took about five minutes to register. By lunchtime the team were discussing paternity, immigration and criminal investigation. His wife suggested forensics.
The first case, and its overlooked half
Two teenage girls had been murdered in nearby villages. A young man had confessed to one of them.
Jeffreys tested the confession against the evidence. It didn't match. The first thing genetic fingerprinting ever did in a criminal case was prove someone innocent — someone who had already confessed to a crime he hadn't committed.
Only afterwards, following a mass screening of thousands of local men, did it identify the actual killer. He had persuaded a colleague to give a sample in his place, and was caught when that colleague was overheard admitting it in a pub.
What it changed
Identity stopped being a matter of testimony. Before, a case rested on what people said they saw. Afterwards, an argument could be settled by something the accused had left behind without knowing.
The exonerations are the part most people miss. In some jurisdictions the technique has freed more people than it has convicted — and it changed what a confession is worth. It turns out people confess to things they didn't do far more often than is comfortable.
DNA Profiling Pioneered is card #246 in the Legacy Domination collection — a trading card game where every card is a real moment in history. [Explore the collection →]
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