Authentication of gadoids from highly processed products susceptible to include species mixtures by means of DNA sequencing methods

Economic importance of gadoids such as fishing resource, and their conservation status, necessitates the development of techniques that allow unequivocal authentication of products made from them. Amplification of a fragment of mitochondrial cytochrome b (cyt b) marker and subsequent phylogenetic analysis were carried out to authenticate these products and assure their correct labeling. Also, SNP analysis that allows detection of species mixtures of Gadus genus was developed. For this, two fragments of the cyt b gene were amplified and sequenced, one of 464 bp and another internal fragment to this of 263 bp to allow the authentication of gadoid species in highly processed products. Obtained sequences were aligned and analyzed in order to assess the presence of informative variable positions and a maximum of 14 SNP were identified and selected. These allow detection and identification of species mixtures belonging to this genus. The developed methodologies were validated and applied to 25 commercial samples. The main novelty of this work lies in the fact that is the only work that allows the detection of species mixtures of the Gadus genus and is the only one that allows the authentication of highly processed products up to date. Furthermore, this methodology allows identifying more of 15 species of gadoids and can be applied to all kinds of seafood products. Therefore, this molecular tool can be applied in questions related to check the fulfillment of labeling regulations for seafood products, verify the correct traceability in commercial trade and for fisheries control.