DNA BARCODING OF CARDINAL FISHES OF THOOTHUKUDI COAST

Cardinal fishes belong to the family; Apogonidae is cryptic in nature that often shows taxonomic ambiguity through conventional taxonomy. It is globally accepted that mitochondrial DNA marker i.e., Cytochrome C Oxidase subunit I (COI) can be used to resolve these taxonomic uncertainties. In the present study, the DNA barcode was developed using COI marker (Fig. 1) for the two species of cardinal fishes (Archamia bleekeri and Ostorhinchus fleurieu) collected from Thoothukudi coast. The COI gene showed the average distance values between A. bleekeri and O. fleurieu were 7.39, 8.14, 7.18 and distance values among the A. bleekeri and O. fleurieu were 4.83 and 4.24, 7.42, 3.72 respectively using K2P parameter.

The estimated GC content of A. bleekeri and O. fleurieu was (49.9%) and (47.6%) respectively and the average GC content was found to be 48.75%. Phylogenetic tree was constructed for the two species using MEGA 6.0 software and the Neighbour-Joining tree showed that A. bleekeri was closely related with Cheilodipterus intermedius and A. bleekeri_2, but Taeniamia buruensis, T. zosterophora, T. kagoshimanus, C. macrodon and Pristicon rhodopterus sequences were distantly related, so they were under another node and O. fleurieu was closely related with O. aureus_1, 2 and 4. The other related species were O. flagelliferus_3, O. aureus_5 but were distantly related with O. fleurieu, so they were comes under another node of the phylogenetic tree (Fig. 2). DNA barcode sequences of the two species of cardinal fishes were submitted to GenBank and the accession numbers obtained for A. bleekeri and O. fleurieu were MF401074, MF401075 and MF401071, MF401072 and MF401073 respectively. In conclusion, the present study developed DNA barcode database for the two species of cardinal fishes that can be used for taxonomic identity of these species.