Analysis of DNA fingerprints at ICI Cellmark Diagnostics, Oxfordshire. Two technicians are working with X-rays (or autoradiographs) of bands of DNA produced by the technique of electrophor- esis in an agarose gel. The pattern of these DNA bands is unique to each individual, but some bands are shared by related people, such as a parent & child. The workers are identifying bands common to mother & child (in red), and father & child (in blue). DNA fingerprints can be used to prove conclusively whether people are related, for instance in cases of disputed paternity, or where immigrants to a country need to prove a family relationship.