Abstract

Today, the fisheries and aquaculture sector contribute with the ~20% of the protein consumed in the world food system. Chile is an important seafood exporter, and Clams are the third produced mollusc in the country behind the giant squid and Mytilus chilensis mussel. Clams are very appreciated for gastronomy, however to enter to the European market they must comply the labelling and traceability regulation, including in the label the commercial and scientific name of the species (EU.1379 2013). There are at least nine different species of edible clams described in Chile. Among them, Ameginomya antiqua, Protothaca thaca, Semele solida, Mulinia edulis and the baby clam Tawera gayi are included in international lists of admitted trade names of fishery and aquaculture species (i.e., Res. 9026 2019, Ministerio de Agricultura, Pesca y Alimentación, Spain 2019). However,another clam species also have the potential to be exported (Gari solida, Eurhomalea rufa, E. lenticularis and E. exalbida). To give confidence in the quality and safety of seafood products, for example, to identify the presence of potential allergens, is essential to correctly and accurately identify the species. Species identification based on morphological traits is difficult to perform in processed products when the shell is removed. In these cases, “DNA barcoding analysis” is a reliable and cost-effective method for species identification to fulfil and enforce the European Union labellinglaw(i.e., Regulation EU.1373 2013). This technique is validated and standardized in vertebrates, however, in molluscs is no consensus about the best barcode genes to perform this analysis. In Chile, the lack of official and commercial methods to identify clam species hampers the export of this resource to the European Union, affecting negatively the production chain and the coastal communities employability and incomes. Our goal is to use DNA barcoding to identify these nine edible clam species. Consequently, we amplify the mollusc 18S rRNA mini-barcode, and compare it in NCBI database using BLAST. Only three species gave 18S rRNA mini-barcode successful amplifications, obtaining fragments of 169pblength in Gari solida and Tawera gayi , and 170pbin Semele solida. BLAST search revealed a lack of sequences of this small mini-barcode 18S rRNA gene in genebank database for these species, but found some high similarity with other related mollusc species. S. solida matches with 100% of identity and 98% of coverage with S. carnicolor and S. zebuensis. Tawera gayi sequence showed a 100% of identity and coverage with the small clam Irus irus. In Gari solida no published sequence reaches the identity of 98% for a confident species identification. These preliminary results revealed the need of developing a local and taxonomically curated of mini-barcode sequences database, and using more barcode genes to increase the taxonomic coverage of this technique.