Studies on DNA barcoding of COI and Cyt b in Taiwanese Monacanthidae and related products

[[abstract]]?DNA barcode? was defined in 2003 by Hebert. The cytochrome c oxidase I (COI) was the target gene for species identification as a DNA barcode. However, most studies on fish species identification focused on the cytochrome b (Cyt b) gene as a DNA barcode of fish. Always, morphological characters of fish were partially or completely lost during processing, and it was difficult to identify the species of commercial fish products by externals. Commercial products were sometimes mislabeled or substituted by toxic or lower price fish species. The aim of this study was compared the divergency of COI gene and Cyt b gene of Monacanthidae in Taiwan seacoast, and chosen the suitable target gene as DNA barcode for identifying the commercial products. Aluterus monoceros, Aluterus scriptus, Cantherhines dumerilii and Monacanthus chinensis were collected from the seacoast of Taichung and Kaohsiung county in Taiwan. The commercial products of dry dressed fish fillets and fish cans were purchased from Ilan. 1553 bp of COI gene and 1141 bp of Cyt b gene were amplified by seven sets of primer. The homologous of Cyt b gene among these four species were from 74.25% to 89.06%. Homologous of COI gene among these four species were from 77.63% to 85.34%. The gene map was also shown that there were more point mutation in Cyt b region than COI region. In this study, we desiged a new set of common primer for amplifying 158 bp fragment in Cyt b gene region, and used for amplifying the degraded DNA from commercial products. After comparing the 87 bp of Cyt b gene of 12 dry dressed fish fillets and 6 can samples, the results shown that their fish source were not Monacanthidae which were all mislabeling. Therefore, it was the molecularly based study of Monacanthidae diversity and sheds light on the evolution and taxonomy of this major fish family and their commencial products