DNA Fingerprinting History
It’s the late 1970s and early 1980s and we’re in the laboratory of Alec Jeffreys, the man who invented DNA fingerprinting. It’s a small lab in the University of Leicester in the UK. He’s putting in many hours studying human inherited variation, which starts from differences in the genes. He’s hunting for sections of DNA that are highly variable from individual to individual as he wants to find out how people vary in their DNA sequences.
The genetic code is written in our genes and the four chemical bases that make up DNA - A, C, G and T. These sequences vary from person to person and help to make each one of us unique. Some of those variations can be highly dangerous; a single base change can lead to a fatal disease. There are many other variations in our genes that make individuals different from each other, but these do not have an affect on our well being.
Jeffreys and his colleagues were one of the first groups anywhere in the world to be able to spot these kinds of variations. However, the technology was limited and they were only spotting small differences. They believed that there would be lots of highly variable sections of DNA, in particular sequences of DNA that would be repeated over and over again. These are known as minisatellites. What would be different between people would not necessarily be the actual DNA sequence of this repeated segment, but the number of times the segment was repeated. The overarching reason for this research was to find genetic markers for specific diseases.
But he needed to detect these minisatellites to back up the theory. A DNA probe was designed and constructed to react with minisatellites in a myoglobin gene. It was mixed up with a bunch of DNA, and if the highly repeated segments were there, they would react with the probe. This DNA came from one of his lab technicians, her mum and her dad.
The Eureka moment for the man who invented DNA fingerprinting came at 9:05 am on Monday 10th September 1984, and it changed his life. When looking at the photographic plate he saw a clear pattern of inheritance between the individuals. The potential for sorting out family relationships and spotting the differences between people was seen immediately.
In interviews and lectures Jeffreys attributes one of the reasons that DNA fingerprinting took off was that he actually called the technology ‘DNA fingerprinting’ rather than the more usual tradition of giving a new technique a complex scientific name.
Its first application came very quickly. Two weeks after the paper appeared in Nature a lawyer got in touch with Jeffreys wanting to use the technology to help resolve an immigration dispute. DNA fingerprinting was used for the first time and it successfully resolved the dispute.
Once the technology was refined a little further it was ready to be used in criminal investigations, and its first successful use was to establish the innocence of man who’d been accused of murder and rape. The technology was then used to find the person who had committed the crime.
Since then DNA fingerprinting has been used to solve thousands of crimes. Alec Jeffreys is now Sir Alec Jeffreys; he received his knighthood for Services to Science and Technology and is one of the most famous scientists of his generation.