Sir Alec Jeffreys – The Man Who Invented DNA Fingerprinting

Alec Jeffreys (Image from Wikimedia Commons)British geneticists Sir Alec Jeffreys is the one who invented DNA fingerprinting in his laboratory at the University of Leicester. Sir Jeffrey’s invention of DNA fingerprinting has revolutionized forensic science and society. This article is a short overview on the history of DNA fingerprinting: how Alec Jeffreys discovered the technology and the impact of this invention in the sciences.

Discovery of DNA Fingerprinting

The DNA sequence of an individual is 99.9% similar to the DNA sequence of another individual whether they are relatives or not. The less than 1% dissimilarity in DNA sequence is enough to distinguish one individual from another. Differences in DNA sequences that cause human variation was the focus of study of Sir Alec Jeffreys (and his colleagues) before he discovered DNA fingerprinting in his small laboratory at the University of Leicester in the U.K. Jeffreys is looking at DNA segments that are highly variable from one individual to individual.

Jeffreys was searching on particular DNA segments or sections that would be repeated over and over again. He called this DNA sections as minisatellites, also known as variable tandem repeats (VTRs). What makes people different from each other is the number of times the DNA segments or minisatellites are being repeated. Closely related individuals are very similar in the number of times a specific minisatellite is repeated.

Jeffreys designed and constructed a DNA probe which he would react the minisattelites of the myoglobin gene. He used DNA samples from one of his laboratory technician’s parents and the technician himself.  If the minisatellites are present in the DNA samples, they would react to the DNA probe.

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The eureka moment of the man who invented DNA fingerprinting occurred on Monday, 9:05 am, September 10, 1984, the most memorable day of the history of DNA fingerprinting. When he was viewing the X-ray film image of his DNA experiment, he observed a clear pattern of inheritance in his lab technician’s family. The image showed both the similarities and differences between the technician’s DNA and his parents. Jeffreys realized the potential of the discovery in identifying individuals. He decided to call the technology as DNA fingerprinting, rather than calling it in a complex scientific name which is the usual practice of naming new techniques.

Jeffreys published his discovery in the journal Nature with the title “Hypervariable ‘minisatellite’ regions of the human DNA’ in the same year.

DNA fingerprinting was made commercially available in 1987 when ICI, a chemical company, started a blood testing center in England.

Applications of DNA Fingerprinting

Two weeks after Jeffreys work appeared at the journal Nature, a lawyer asked him if he could use DNA fingerprinting to solve an immigration dispute involving a boy with Ghanaian descent who is in danger of being deported to Ghana. His relationship to a British family of Ghanaian origin is being challenged. Using DNA fingerprinting technology, it was proved that the boy is closely related to the members of the family. This was the first application of DNA fingerprinting.

DNA fingerprinting was used to find the person who raped and murdered two young teenagers in Narborough, Leicestershire on 1983 and 1986 respectively. The DNA from the semen found in the girls’ dead bodies matched the DNA of Colin Pitchfork. British authorities said that without DNA fingerprinting, the main suspect, Richard Buckland, should have been the one convicted for rape and murder. This was the first application of DNA fingerprinting in forensic science; since then, the technology was used to solve thousand criminal cases where only DNA samples from blood, semen, saliva, tissues, and other body fluids are found in the victims’ bodies or crime scenes.

DNA fingerprinting has also been used to solve paternity disputes. Males claiming to be the father of a child just need to submit samples of their DNA for paternity testing. Anyone of them who matches the DNA of the child is the biological father and has the legal rights over the child.

DNA fingerprinting has also been used in wildlife genetics studies.[ad#afterpost]