Molecular Phylogeny based on nuclear ribosomal DNA Internal Transcribed Spacer 2 (rDNA ITS2) gene in the Anopheles species (Culcidae: Diptera)

Abstract

Phylogenetic studies mostly employ non-coding regions of large proportion of nuclear DNA markers because they are usually more variable than coding regions. DNA sequence analysis of 2nd Internal Transcribed Spacer (ITS) region was carried out among six Anopheles species within the subgenus Cellia. The results indicated high variance of spacer mutants in the genus Anopheles. The phylogenetic trees were generated by all the three methods i.e. MP, ML and NJ and showed that both stephensi and maculatus form a single clade. The ITS2 sequences varied between 453-506 base pairs and were slightly G-C rich. As per the incidence of substitution, the rate of transversions 66.78% was found to be more than transitions 29.68%. As a result of the present data it had been possible to examine the usefulness of the ITS 2 in the nuclear ribosomal gene array for conducting a phylogenetic analysis of selected taxa within the genus Anopheles. The aim of the present study was to assess the suitability of ITS2 gene for species level analysis and the current data provides useful reference for further work.