DNA testing. Multi-pipette being used to add 8 samples of DNA (deoxyribonucleic acid) to an electrophoresis gel tray. DNA is the genetic material that controls the growth and development of living organisms. The DNA here has had a blue dye added so that it can be seen. The gel will then have an electric field applied to it to separate the DNA samples into their component parts to form a sequence of bands. This can then be used to find out if a parent and child have the same genes, or whether someone who has no symptoms carries a disease gene that could be passed to their children.