DNA Fingerprinting

The Discovery of DNA Fingerprinting

In September 1984, Dr. Alec Jeffreys, a geneticist from the University of Leicester in Great Britain was studying hereditary diseases in families. He was focusing on methods to resolve paternity and immigration disputes by demonstrating the genetic links between individuals. Jeffreys used Restriction Fragment Length Polymorphism (RFLP) to analyze Deoxyribonucleic Acid (DNA). Dr. Jeffreys discovered that repetitive patterns of DNA, known as Variable Number of Tandem Repeats (VNTRs), were present in all human beings but that they varied in length for each individual. He soon realized that this variation could be used to establish the identity of a person and he named his technique genetic fingerprinting. Dr. Jeffreys demonstrated that a genetic fingerprint is specific to each individual and the pattern does not belong to any other person on earth except for identical twins.

Jeffreys' DNA fingerprint technique would be catapulted into the world of forensic science when two murders were committed not far from the University of Leicester. For the first time, genetic fingerprinting would be used to exonerate a suspect and convict the guilty person.

The quiet little village of Narborough in Leicestershire, East of Birmingham, would be put on the forensic map when two crimes shocked residents and law enforcement. In 1983, 15-year-old Lynda Mann was found raped and murdered. Three years later, Dawn Ashworth, also fifteen, was also raped and murdered.

With the use of RLFP based DNA technology, Dr. Jeffreys was asked to compare semen samples from both murders against a blood sample from a seventeen year old suspect, Richard Buckland, who was in police custody and who had confessed to the second crime. This confession raised suspicion among some detectives, as Buckland had to be 14 years old when he committed the first crime. Dr. Jeffreys' DNA tests proved that the DNA fingerprint from the semen found on the two murdered victims was not the same as Buckland's. It also proved that the same killer was responsible for both crimes.

With this information, law enforcement then took an unprecedented task to catch the killer. The first DNA dragnet was used. A total of 4,582 men, from three towns, were tested for the killer's blood type, (type A) and enzyme PGM +1 retrieved from his semen (Wambaugh, 1989) Ten per cent of the men tested had the same blood type and enzyme as the killer and their blood was subsequently tested by Jeffreys' genetic fingerprinting technique.

A local baker named Colin Pitchfork avoided having his blood tested. He gave a colleague, Ian Kelly, his passport in which he had replaced his picture with Kelly's photo. Then Pitchfork had Kelly submit his own blood for him. Months later his ploy was discovered by law enforcement when a resident came forward after hearing a conversation at a local pub in which Kelly admitted that he was paid by Pitchfork to have his blood tested. This led to the arrest of the twenty seven-year old Pitchfork. Dr. Jeffreys compared Pitchfork's DNA with the DNA of the semen found on the two victims. It was a perfect match. Instead of going to trial, Pitchfork pled guilty to both rapes and murders.

In 1987, Pitchfork became the first person in the world to be identified, captured and successfully prosecuted as a result of DNA evidence. He was sentenced to life, minimum term of 30 years, and is currently in prison for both murders. In May 2009, Pitchfork had his life sentenced reduced by 2 years.

In 1994, Professor Jeffreys was knighted by The Queen of England and today he is still a Professor in the Department of Genetics at the University of Leicester in Great-Britain.

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