DNA barcoding of true limpets (Order Patellogastropoda) along coast of China: a case study

In this study, we applied a partial sequence of mitochondrial COI gene as DNA barcode to assess the viability of DNA barcoding for distinguishing Patellogastropoda. One-hundred thirty-five COI gene sequences were obtained from 13 species belonging to Nacellidae (Cellana) and Lottiidae (Lottia, Patelloida and Nipponacmea) along the coast of China. The alignment result of these sequences indicated the existence of insertions in mitochondrial COI gene of Patellogastropoda. The Kimura 2-parameter (K2P) distances within species and genera were 0.00-1.01% (average 0.07%) and 18.09-37.80% (average 24.07%), respectively, an obvious barcoding gap existed. All species in our study were clearly discriminated in all trees (neighbor-joining (NJ), Bayesian, and maximum likelihood (ML) tree) with a highly supported clade node. The character-based barcode method successfully identified 100% of the Patellogastropod species included, and performed well in discriminating Patellogastropod genera. The results of this study affirm that DNA barcoding based on the COI gene can identify species belonging to Patellogastropoda rapidly and accurately.