DNA fingerprints from a murder case.

This autoradiograph shows that DNA in blood from the defendant's clothes matches the DNA fingerprint of the victim but differs from that of the defendant.

This is evidence that the blood on the defendant's clothes came from the victim, not the defendant.

The three DNA samples were subjected to Southern blotting using radioactive probes.

PCR can also be used to amplify the amount of DNA collected at the crime scene.