Approccio biomolecolare per l'identificazione di specie di una trancia di pesce / A DNA-based approach in species identification of frozen fish

Part of the cytocrome b (cyt. b) and 16S rRNA genes were sequenced to identify a frozen fish steak labelled as cernia ruvet-to (R. pretiosus), common name oil fish. Authenticated individual of R. pretiosus was used as reference: undoubtful identification was done by morphology. Consumption of this species has been reported to have purgative effects in some consumers, and the trade of R. pretiosus and other related species in Italy is forbidden. Alignment of the obtained sequences with those available in GenBank data base was carried out with BLASTn and genetic distances were calculated using the Tamura-Nai model. Reference oil fish showed 100% homology with sequence of R. pretiosus available in GenBank, while unknown sample achieved the highest homology with Lepidocibium flavobrunneum (97%). This approach is rapid and offers the potential to detect fraudulent or unintentional mislabelling of seafood. For an unambiguous answer to the question of similarity and intra-species polymorphisms, further authenticated individuals of different geographic origin should be investigated and a greater number of species shoulds be sequenced so as to apply the test as a routine seafood authentication analysis.