DNA fingerprinting used to prove family relation- ships. The photo shows part of an X-ray (or autoradiograph) of bands of DNA produced by the technique of electrophoresis 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. DNA fingerprints can be used to prove conclusively whether people are related. The bands in these DNA fingerprints are marked M for mother, C for child, F for father. In this case, the mother's bands have been marked in red, the father's in blue. Both children share some bands with each parent, proving that they are indeed related.