Evolutionary dynamics of the mitochondrial genome in the evaniomorpha (Hymenoptera)-A group with an intermediate rate of gene rearrangement

Abstract

We determined the complete mitochondrial (mt) genomes of three evaniomorph species, Ceraphron sp. (Ceraphronoidea), Gasteruption sp. (Evanioidea), and Orthogonalys pulchella (Trigonalyoidea) as well as the nearly complete mt genome from another evaniomorph species,Megalyra sp. (Megalyroidea). Eachof thempossessesdramatic generearrangements, includingprotein-coding orrRNAgenes.Geneinversionswereidentified inall of thesemtgenomes; forexample, the tworRNAgeneshave invertedandmoved into thenad2-cox1junction in the Megalyra sp.mtgenome.In addition,wefound twocopies of a 10-bpcomplementary repeat at the beginning of rrnS and at the end of trnL2 in the Gasteruption sp. mt genome, consistent with recombination as the possible mechanism for gene inversion and long-range movement. Although each of the genomes contains a number of repeats of varying size, there was no consistent association of the size or number of repeats with the extent or type of gene rearrangement. The breakpoint distance analysis showed the Evaniomorpha has an intermediate rate of gene rearrangement. Sequence-based phylogenetic analyses of 13 protein-coding and 2 rRNA genes in 22 hymenopteran taxa recovered a paraphyletic Evaniomorpha with the Aculeata nested within it. Within the Evaniomorpha, our analyses confirmed the Trigonalyoidea +Megalyroidea as the sister group to theAculeata and recovered a novel clade,Ceraphronoidea+ Evanioidea. In contrast to previous hymenopteran phylogenetic studies, the internal relationships of the Evaniomorpha were highly supported and robust to the variation of alignment approach and phylogenetic inference approach. © The Author(s) 2014.