DNA barcoding of Indian ant species based on cox1 gene

Sixteen species of ants collected from Karnataka, India, were sequenced and barcoded for a 658 bp region of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). This gene is frequently termed as CO1 in barcoding approach and serves as the core of a global bioidentification marker for insects and other animals. The AT content in DNA of 16 ant species was estimated as 68.55%, which is in accordance with invertebrates. The variance of AT content among species was much higher for the 1st base (AT(1)) compared to the 2nd and 3rd bases, which were nearly invariant. The distance within species was calculated using Kimura 2-parameter (K2P) and it was 0.166, 0.000 and 0.333% for mean, minimum and maximum, respectively. Moreover, our data also showed some phylogenetic signal. In a neighbor-joining tree for all sequences, two clusters were obtained, the first cluster consisted of subfamilies Formicinae and Myrmicinae, while other clade showed relationship between subfamily Myrmicinae and Ponerinae clustered with subfamily Dolichodrinae, which is not in contradiction with cladistics analysis of morphological data for ants and is consistent with traditional phylogeny of ants. The present results thus favour DNA barcoding as a decisive tool in quick and reliable identifications of ants.