DNA barcoding is a useful tool for the identification of marine fishes from Japan

In this study, 229 DNA sequences of cytochrome oxidase subunit I gene (COI) from 158 marine fishes of Japan were employed to test the efficacy of species identification by DNA barcoding. The average genetic distance was 60-fold higher between species than within species, as Kimura two parameter (K2P) genetic distances averaged 17.6% among congeners and only 0.3% among conspecifics. There were no overlaps between intraspecific and interspecific K2P distances, and all sequences formed species units in the neighbor-joining dendrogram. Hybridization phenomena in two species (Kyphosus vaigiensis and Pterocaesio digramma) were also detected through searches in Barcode of Life Data Systems (BOLD). DNA barcoding provides a new way for fish identification.

Research highlights
► DNA barcoding, which was advocated by Hebert et al., seeks to facilitate identifying the increasing number of unfamiliar taxa in biological conservation and biodiversity surveys, based on sequence diversity within a short and standardized gene region. So far, scientists from over 30 different countries have participated in this large international plan, which will cost about 1.5 billion for build up species tags for each eukaryote.
► Fish are the largest group of vertebrates, which exhibit a remarkable diversity of morphological attributes and biological adaptations. Species identification is challenging for taxonomists when facing new biotas. However, DNA barcoding has proven powerful in some cases where the morphological taxonomy is little to the purpose of species identification.
► Herein, 229 sequences from 158 marine fishes of Japan were employed to test the efficacy of species identification by DNA barcoding. There were no overlaps between intraspecific and interspecific K2P distances, and all sequences formed species units in the neighbor-joining dendrogram. High efficiency in species identification by DNA barcoding was demonstrated in this study.