MODEL RELEASED. DNA fingerprinting. Male technician examines a DNA sequencing autoradiogram or genetic fingerprint". A sample of DNA can be taken from body tissue such as hair, blood and saliva. The sample is then segmented with enzymes and a process known as electrophoresis orders the segments by size. The segments are then exposed on X-ray film where they form bands of black bars. Each band represents the position of the four DNA bases which forms the unique genetic code. The banding is unique to each individual and it is this that is known as the "fingerprint". It can be used to prove people are related and can help identify criminals."