A Molecular Framework for the Phylogeny of the Ant Subfamily Dolichoderinae

Abstract

Partial sequences are reported for the mitochondrial genes for cytochrome oxidase subunits 2 and 3 and for cytochrome b, and the entire sequence of the gene for tRNALeuUUR for species from 14 genera of dolichoderine ants and from three outgroup genera. Considerable variation was observed between tRNA genes in the size of the TΨC arm and the DHU and anticodon loops and whether or not the TΨC stem possesses a GC pair. The outgroup taxa showed complete TAA CO1 stop codons, but dolichoderines have either TA or T. The outgroup taxa showed a noncoding gap between the CO1 and the tRNALeuUUR genes. A phylogeny-independent compatibility test using the amino acid sequences showed differences between the genes consistent with variation in evolutionary rates, according with other studies. Base compositions proved heterogeneous between species, hence phylogenetic analysis was restricted to the protein sequences using maximum likelihood and the mtREV24 replacement matrix. A maximum-likelihood consensus tree has similarities to those from morphological studies with some exceptions such Leptomyrmex falling within the dolichoderine genera rather than basally, and the accretion of genera formerly included under Iridomyrmex. Features of the tRNA genes and the CO1 termination codons agree quite well with the molecular phylogeny.