Laboratory glassware and DNA profile. A bottle and petri dishes containing coloured fluids. At the top of the image is a DNA profile. A DNA profile is made when selected DNA extracted from the blood is separated into DNA bands by electrophoresis in an agarose gel. The pattern of DNA bands 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 conclusively whether people are related. It can also be used to identify and convict criminals from blood, semen or hair left at the scene of a crime."