DNA fingerprinting

DNA fingerprinting has become a permanent part of society, helping to prove innocence or guilt in court cases, resolving arguments in court. It was invented by Professor Sir Alec Jeffreys, University of Leicester.

The chemical formation of everyone's DNA is the same. The only difference between people (or animal) is the order of the base pairs. There are so base pairs in each person's DNA that everyone has a different order. Using these sequences, every person could be recognized only by the sequence of their base pairs. However, because there are so many base pairs, the task would be very long. Instead, scientists are able to use a shorter method, because of repeating patterns in DNA. These patterns do not give an individual "fingerprint," but they are able to resolve whether two DNA samples are from the same person. Scientists use a small number of sequences of DNA that are known to be different among people a great deal, and analyze those to get a definite chance of a match.