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Frauds and fish species authentication: Study of the complete mitochondrial genome of some Sparidae to provide specific barcode markers

Ceruso, Marina, Mascolo, Celestina, Anastasio, Aniello, Pepe, Tiziana, Sordino, Paolo
Food control 2019 v.103 pp. 36-47
DNA barcoding, NAD (coenzyme), Sparidae, conserved sequences, cytochrome-c oxidase, fish, genes, genetic variation, markets, mitochondria, mitochondrial DNA, mitochondrial genome, nucleotide sequences, polymerase chain reaction, prices, ribosomes, sensory properties, sequence alignment, species identification
Sparids have different organoleptic properties that correlate with a wide variety of retail prices in the market. Components of the observed morphology are rarely sufficient for full identification of these fish species, whose authentication requires specialist knowledge. Genetic diversity or variation and their measurements enable molecular methods as one of the most suggested remedies for aliud pro alio frauds. Genetic approaches have the potential for reducing costs and providing correct identification for a large number of market products. Mitochondrial (mt) DNA sequences (16S and 12S ribosome subunits, cytochrome b-CYTB, and cytochrome c oxidase I-COI) have been widely used for fish species identification. Yet, these mtDNA regions perform well for certain species but are less discriminating for others. Here, we report the first study of the whole mtDNA of the perciform fishes of the family Sparidae with the aim to select more efficient barcoding markers for taxonomical discrimination against frauds. For species-level sequence information, we analyzed and compared the whole sequence of thirteen Sparidae mitogenomes, nine publicly available and four recently sequenced ones. In particular, we searched for effective DNA barcode markers for the correct identification of sparid species by looking for interspecific variable regions flanked by conserved sequences for PCR primer design. We found that only four mtDNA genes are devoid of insertions or deletions, which can complicate the process of sequence alignment. Among them, NAD genes show encouraging utility in discriminating closely related sparid species owing to nucleotide sequence variability compared with classical barcodes for species. Discrimination capacity of NAD genes suggests their application as alternative mtDNA tools for the identification of Sparidae fishes. In particular, NAD5 fragments with high interspecific nucleotide sequence divergence were amplified and appear flawless for Sparidae species identification.