Decoding the molecular phylogenetics of ornamental catfishes (siluriformes) of North East India using DNA barcoding approach.

BACKGROUND: Catfishes (order Siluriformes) are among the most diverse and widely distributed fish groups in the world. They are not only used for human consumption but are also a major part of the ornamental fish trade. Being a Biodiversity Hotspot, the North Eastern Region of India is home to a diverse population of ornamental fishes. Catfishes contain a humongous number of species; in this study, the authors have tried to elucidate the phylogenetic relationship of some important ornamental catfishes found in North East India using DNA barcodes. METHODS AND RESULTS: In this study, we have tried to explore the phylogenetic history of 13 species (41 specimens) of ornamental catfishes spanning 12 genera and 9 families of Siluriformes using DNA barcoding. Pairwise genetic distances using Kimura 2-Parameter (K2P) were calculated at intra-specific and inter-specific levels. A Neighbor-Joining tree was constructed to understand the phylogenetic relationship among the nine different catfish families. All the specimens under this study clustered with their respective species under the same family and formed three sub-clades. However, Olyra longicaudata, belonging to the Bagridae family, did not cluster with other species from the same family. In this study, the authors have suggested a revision of the classification of O. longicaudata back to its original family, Olyridae. CONCLUSIONS: In this study, the maximum intraspecific genetic distance of 0.03 and the minimum interspecific genetic distance of 0.14 were observed among the species. Therefore, it is evident that there is a barcoding gap among the species, which helped in the correct identification of the species. Thus, DNA barcoding helped complement the phenetic approach and also revealed a different phylogenetic relationship among the catfishes belonging to the Bagridae family.

The complete mitochondrial genome of the medicinal fish, Cyprinion semiplotum: Insight into its structural features and phylogenetic implications.

Assamese kingfish (Cyprinion semiplotum) belonging to the subfamily Barbinae is an important food as well as aquarium fish having identified pharmacological benefits. The species has a complex taxonomic history and its phylogenetic position remains uncertain. Molecular data employed in earlier phylogenetic studies was inadequate for its phylogenetic placement. Therefore, we characterized 16,671 bp long complete mitogenome of C. semiplotum using next-generation sequencing. The mitogenome encodes the typical set of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two non-coding regions. Its gene organization, distribution pattern, nucleotide composition, tRNA secondary structure and codon usage was similar to other Cyprinid mitogenomes. However, a distinctive 90 bp insertion was found in 3' periphery of the AT-rich control region. This can be a tool for identification of the species at the population level. Further, we reconstructed the most comprehensive phylogenetic trees of Cyprinidae based on complete mitogenome. In the resulting phylogenetic trees, C. semiplotum clustered tightly with other Barbinae species and exhibited a sister relationship with the species of the genera Aulopye, Barbus, Luciobarbus and Capoeta. The results presented herein will support future investigations on molecular taxonomy, population genetics, evolution and molecular phylogeny of C. semiplotum and its relatives.