Molecular Taxonomy of Serranidae, Subfamily Epinephelinae, Genus Plectropomus (Oken, 1817) of Andaman Waters by DNA Barcoding Using COI Gene Sequence

Abstract

Abstract DNA barcoding is an efficient method of biological sample identification and it has been advanced as a promising tool to aid species identification through use of the mitochondrial Cytochrome C Oxidase subunit I (COI) gene as standardized region. For a variety of reasons the identification of fishes can be problematic, even for experts, through conventional taxonomic studies. So, the present study was designed for identification of Plectropomus species. Species of this highly morphologically ambiguous genus were identified through COI gene sequence analysis. The fish samples were collected from the seas of South Andaman during 2010–11 and morphologically identified using standard traditional taxonomic keys of the Food and Agriculture Organization (FAO). A standard protocol was adopted for the PCR amplification of the 650–655 bp COI genes, which were bidirectionally sequenced from 20 specimens (mean of 6 specimens/species). The COI gene sequences of all the specimens were interrogated using analytical tools available on the Barcode of Life Data System (BOLD) and National Center for Biotechnology Information (NCBI) GenBank. All the studied species showed 99 to 96 percent genetic identity and formed discrete clusters of closely related haplogroups. The present study identified through COI gene sequence analysis the misidentification or misnaming of a reference sequence of P. leopardus and P. pessuliferus. The studied species exhibited close genetic relationships with the same species from Australian waters. Further, this is the first documentation of COI gene sequences of the genus Plectropomus from the Andaman region. This study constitutes a significant contribution to the global barcode reference sequence library for fish and demonstrates the utility of barcoding for regional species identification. The morphologically more similar P. leopardus and P. maculatus were analyzed using COI gene sequences, and distinct genetic distances were found between them. It is suggested that consideration be given to revising the morphology-based taxonomy checklist with a view to reclassification of this genus in the Andaman and Nicobar Islands.