Northwest Fisheries Science Center

Case examples: Individual ID

Salmon fillets Salmon fillets

Forensic evidence submitted: Cleaned salmon carcasses found on a dock and several salmon fillets recovered from the suspect’s freezer.

Violation: Wasting Violation: Tribal code prohibiting dumping fish products

Techniques employed: Use STR markers (microsatellites) to match carcass DNA to fillet DNA.

By using several independent DNA markers that are highly variable in salmon, DNA types can be directly compared between two tissues. The DNA signature or “fingerprint” will be identical in all tissues from the same individual. Using several STR loci we were able to establish a match identity with high statistical probability. Forensic geneticists matched the fillets recovered from the suspects freezer to the carcasses found on the dock.

STR markers STR markers

DNA analysis results: Fillets and carcasses were “matched” with a high statistical probability. The probability of two different fish having the exact same DNA fingerprint was determined to be very unlikely.