DNA barcoding coupled to HRM analysis as a new and simple tool for the authentication of Gadidae fish species

•DNA barcoding was combined with High Resolution Melting (HRM) analysis.•COI and cytb barcode regions were exploited for Gadidae species differentiation.•Atlantic cod, Pacific cod, pollock and saithe were identified successfully.•Cytb was the most efficient barcode to differentiate the four species by HRM analysis.•A new, rapid, simple and cost-effective tool was proposed for codfish authentication.

This work aimed to exploit the use of DNA mini-barcodes combined with high resolution melting (HRM) for the authentication of gadoid species: Atlantic cod (Gadus morhua), Pacific cod (Gadus macrocephalus), Alaska pollock (Theragra chalcogramma) and saithe (Pollachius virens). Two DNA barcode regions, namely cytochrome c oxidase subunit I (COI) and cytochrome b (cytb), were analysed in silico to identify genetic variability among the four species and used, subsequently, to develop a real-time PCR method coupled with HRM analysis. The cytb mini-barcode enabled best discrimination of the target species with a high level of confidence (99.3%). The approach was applied successfully to identify gadoid species in 30 fish-containing foods, 30% of which were not as declared on the label. Herein, a novel approach for rapid, simple and cost-effective discrimination/clustering, as a tool to authenticate Gadidae fish species, according to their genetic relationship, is proposed.