First genetic fingerprint, 1984.
© Science Museum / Science & Society Picture Library
An autoradiograph of the first genetic fingerprint prepared by Alec Jeffreys at Leicester University on 19 September 1984. Jeffreys was the first to discover a series of probes to hypervariable DNA sequences. These regions of DNA consist of many repeats of the same sequence (tandem repeats). Since hypervariable DNA differs markedly from individual to individual, the presence of common bands between individuals indicates a relationship. In conjunction with the technique of 'Southern blotting' (named after Ed Southern, its developer), Jeffreys developed a method of analysis by which he could look at these sequences and observe differences between individuals in a population. This technique has wide applications in forensic science.