Uses restriction enzymes to cut / chop DNA everywhere a specific base sequence occurs (always the same), produces restriction fragments.
1. DNA from different microorgs treated with same restriction enzyme, which produces restriction fragments. (DNA placed in wells)
2. Restriction fragments are separated by electrophoresis (apply electrical current to gel to separate the fragments by size and electrical charge)
3. Comparison of results. The more similar the paterns (DNA fingerprints), the more closely the organisms are related, or if different, no relation.