What Is DNA Fingerprinting?

DNA fingerprinting is a technique used in forensic medicine. It was first used in criminal cases in the UK in the late 1980s. Robert Melias was the first man in the UK to be convicted of rape on the evidence of DNA fingerprinting. The technique has been used in many cases since but it can be controversial.

The method of DNA fingerprinting, or DNA profiling was developed in 1984 at Leicester University by a researcher called Alec Jeffreys. The idea behind it is to compare samples of DNA from a crime scene to see if it has any sequences that match with DNA from a known suspect.

Each cell in the human body contains a nucleus with DNA, wound up into 46 chromosomes. The sequences of DNA in different genes vary between different people and the pattern of an individuals DNA can be mapped. Basically, a DNA sample is purified to remove proteins and other contaminants, then digested by special enzymes into small fragments. These are sorted into sizes by electrophoresis and detected by radioactive probes. The position of fragments is detected by photographic film and then analysed.