Identification of tuna species (Thunnini tribe) by PCR-RFLP analysis of mitochondrial DNA fragments

Tunas are highly priced and the Atlantic bluefin tuna is most endangered trade fish in the world. For effective fishery management and protection of consumers' rights, it is important to develop a molecular method to identify the species of tuna products. In this study, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was developed to identify 10 tuna or tuna-like species. Primers were designed to amplify six mitochondrial DNA fragments from each specimen, and three restriction enzymes including AfaI, DdeI, and AluI were used to analyze the short length fragments produced from ATPase and control region (CR) genes. Besides these, the phylogenetic relationships among tested fish species were analyzed based on phylogenetic trees constructed using the amplified COI and CR sequences. The results indicated that the developed PCR-RFLP really provided a useful and academic technique to identify high-priced tuna species.