History of DNA Profiling
- DNA profiling, as we know it today, was developed thanks to two independent breakthroughs in molecular biology that occurred at the same time on different sides of the Atlantic. In the USA the polymerase chain reaction (PCR) was invented by Kary Mullis, while in the UK 'DNA fingerprinting' was being discovered by Professor Sir Alec Jeffreys at the University of Leicester.
- In its earliest incarnation this technique was performed by restriction of 0.5–10μg extracted DNA using the restriction enzyme HinFI*, followed by Southern blotting hybridisation* designed to bind to multiple 'minisatellites'* present in the restricted DNA.
- In its earliest incarnation this technique was performed by restriction of 0.5–10μg extracted DNA using the restriction enzyme HinFI*, followed by Southern blotting hybridisation* designed to bind to multiple 'minisatellites'* present in the restricted DNA.
The first DNA profiling conviction
DNA was first used to aid a criminal investigation by Professor Jeffreys in 1986. This investigation used DNA fingerprinting techniques to link semen stain samples, collected from two rapes/murders that had occurred three years apart in 1983 and 1986, in a small village in Leicestershire, UK. The probability of this match occurring by chance was calculated as 5.8 x 10-8. This result not only linked the two crimes and secured the conviction of the perpetrator Colin Pitchfork, but also exonerated an innocent man implicated in the murders and led to the first mass screening project undertaken for DNA profiling in the world.