Genetic Variation in Catfish Family: Ariidae, Bagridae and Plotosidae of India Using MtDNA Cyt B Gene

To find the genetic variation and phylogenetic status of Ariidae, Bagridae and Plotosidae catfishes, this study was performed using mitochondrial cytochrome b (Cyt b) gene sequence. Totally 155 species were used in phylogenetic reconstructions under maximum parsimony, maximum likelihood and Bayesian inference criteria. The oneway ANOVA in base composition distance in Ariidae F= 184.77, df = 3; 6437, P< 0.0001 in Bagridae F= 19.41, df = 3; 1322, P< 0.0001 and in Plotosidae F= 1.40, df = 2; 32, P < 0.0001. The genetic distances between taxa increase as the taxonomic rank increases. In MP, ML and BI based phylogenetic tree of Ariidae, Cathyrops dasycephalus formed the longest branching clade suggesting that it would have accumulated mutations in neutral selection. Most of the other species in this tree showed that they have recently diverged. In Bagridae family, Olyra longicaudatus and Leiocassis argentivittatus are the two species that formed a long branched attraction affecting the related species branched to its major node. Batasio and Bagrichthys genera have combined to form a monophyletic clade. Mystus genus displayed monophyletic group with higher bootstrap and posterior probability values for all the species. Plotosus genus displayed monophyletic group with higher bootstrap and posterior probability values for all the species. The phylogram shows that the branch length of all the taxa except Plotosus canius showed branch length more or less 0.05 depicting moderate substitution rates throughout this genus.

Keywords: MtDNA, Cytochrome b, Catfish, Phylogenetic Analysis, Genetic variation.