Novel gene rearrangement in the mitochondrial genome of Pachyneuron aphidis (Hymenoptera: Pteromalidae).

Species in Hymenoptera usually show exceptionally high rates of mitochondrial molecular evolution and dramatic gene rearrangements, which has been attributed to their parasitic lifestyle. However, mitochondrial genome (mitogenome) of chalcidoid wasps is still poorly understood and the evolution of gene rearrangements is still unclear. In this study, the nearly complete mitogenome of Pachyneuron aphidis, a chalcidoid wasp mainly hyperparasitizes the Aphidius gifuensis, was sequenced using a next-generation sequencing strategy. This genome is 15,137 bp in length, including 13 PCGs, 22 tRNAs, two rRNAs and a partial control region. Alignment with other Chalcidoidea mitogenomes revealed a novel inversion in the srRNA-trnV gene cluster in P. aphidis, which is the first of its kind to be reported in Chalcidoidea. Breakpoint distances analysis showed the high value of chalcidoid wasps compare to the ancestral arrangement pattern, which reflected as extensive gene rearrangements. Despite the high frequency of gene rearrangements in these insects, analyses of gene rearrangement and phylogenetic trees showed that species from the same family and the genus tent to have similar gene orders, and the conserved gene blocks (ND3-trnG, srRNA-trnV and COIII-ATP6-ATP8-trnD-trnK-COII-trnL2-COI) can usually be identified, especially at the family level of chalcidoid wasps.