"The Case of the Falsified Fillets:"
Fisheries applications of DNA Forensics

    The species identity of a fish that has been skinned, cleaned, filleted, cooked, frozen, dried, and / or salted can be difficult to determine. Questions may arise as to the origin of a commercial product, for example, whether the catch in a boat's hold has been properly reported, or whether the label on a package is accurate. In some, a product may be physically altered to pass as another, for example by bleaching of fillets. Although physical identification may be impossible once skin and scales are gone, DNA survives processing in sufficient quantities to provide a reliable test.

    In the test shown here, the identity of four salt-cured fish fillets was questioned. DNA from each was amplified, sequenced, and compared to a DNA data base of known cod, pollock, and hake species. The analysis produces a "family tree", which shows that each fish belongs to a different commercial species: walleye or Alaska pollock, Atlantic cod, Pacific cod, and pollock or saithe.