Laboratory glassware and DNA profile. Coloured negative image of a gloved hand holding a coloured petri dish. A bottle and other petri dishes are seen with a DNA profile in the background. A DNA profile (at upper left) is made when DNA extracted from a person is separated into bands by electrophoresis in a gel. The exact banding is unique to each person but some bands are shared by related people, such as a parent and child. Such DNA fingerprints" can be used to prove whether people are related. They can also be used to identify criminals from blood, semen or hair left at the scene of a crime."