DNA barcoding and molecular phylogeny of genus Pseudagrion (Odonata: Coenagrionidae) based on mitochondrial COI, ND1 and 16S rRNA genes

Genus Pseudagrion is one of the largest genera of order Odonata and 14 species of this genus have been reported in India. The current research aims to reconstruct the phylogenetic trees by amplifying the partial sequences of the following three mitochondrial genes: COI, ND1 and 16 S rRNA genes, to produce a DNA reference library and determine the evolutionary relationships among the species of genus Pseudagrion. Sequences of mitochondrial genes of eight species have been submitted to NCBI, out of which Pseudagrion decorum, P. hypermelas and P. indicum barcoded for the first time. Since no work has been reported to far for CUB in genus Pseudagrion, the MT-ND1 gene appears to be a good choice for analyzing codon usage pattern. Codon usage bias for mitochondrial genes is low because of high effective number of codons. The most frequent codons, favored A or T at the 3rd codon position which indicate the significant role of compositional constraint in codon usage bias. Genetic divergence based on COI and 16 S rRNA ranges from 2.4 to 15.8%. 12 S rRNA and 16 S rRNA genes show minor genetic diversity, whereas NDI and COI genes reveal higher genetic diversity because of high mutation rate. In phylogenetic tree, 34 Pseudagrion species get segregated into five major clades as: ((P. pruinosum + P. spencei + P. hypermelas + P. rubriceps) + P. microcephalum) + (P. decorum + P. indicum + P. australasiae) + ((P. aureolum) + P. massaicum + P. tanganyicum + P. hamoni + P. pacale + P. niloticum + P. acacia) + (P. ignifer + P. pilidorsum + P. pruinosum) + ((P. dactylidium) + P. bicoerulans + P. munte + P. sarepi + P. kersteni) that depicts their evolutionary relationships.