The mitochondrial genomes of Panorpidae: sequence, structure and phylogenetic analysis

Abstract Background: Mitochondrial genomes play a significant role in reconstructing phylogenetic relationships and revealing molecular evolution in insects. However, only two species of Panorpidae have been documented for mitochondrial genomes in Mecoptera to date.Results: We obtained complete mitochondrial genomes of 17 species of Panorpidae. The results show that the complete mitogenome sequences of Panorpidae all contain 37 genes (13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs) and one control region. The mitogenomes exhibit a strong AT bias. The AT-skew can either be slightly positive or slightly negative, while the GC-skew is usually negative. The 22 tRNA genes can fold into a common cloverleaf secondary structure except trnS1. The sliding window and genetic distance analyses demonstrate highly variable nucleotide diversity among the 13 protein-coding genes, with comparatively low evolutionary rate of cox1, cox2 and nad1, and high variability of nad2 and nad6. The phylogeny of Panorpidae can be presented as (Neopanorpa + Furcatopanorpa) + (Dicerapanorpa + (Panorpa debilis + (Sinopanorpa + (Cerapanorpa + Panorpa)))).Conclusions: Our analyses indicate that the genes nad2 and nad6 can be regarded as potential markers for population genetics and species delimitation in Panorpidae. Panorpa is reconfirmed a paraphyletic group.