title: Complete mitochondrial genome of the free-living earwig, Challia fletcheri (Dermaptera: Pygidicranidae) and phylogeny of Polyneoptera.
abstract: The insect order Dermaptera, belonging to Polyneoptera, includes ∼2,000 extant species, but no dermapteran mitochondrial genome has been sequenced. We sequenced the complete mitochondrial genome of the free-living earwig, Challia fletcheri, compared its genomic features to other available mitochondrial sequences from polyneopterous insects. In addition, the Dermaptera, together with the other known polyneopteran mitochondrial genome sequences (protein coding, ribosomal RNA, and transfer RNA genes), were employed to understand the phylogeny of Polyneoptera, one of the least resolved insect phylogenies, with emphasis on the placement of Dermaptera. The complete mitochondrial genome of C. fletcheri presents the following several unusual features: the longest size in insects is 20,456 bp; it harbors the largest tandem repeat units (TRU) among insects; it displays T- and G-skewness on the major strand and A- and C-skewness on the minor strand, which is a reversal of the general pattern found in most insect mitochondrial genomes, and it possesses a unique gene arrangement characterized by a series of gene translocations and/or inversions. The reversal pattern of skewness is explained in terms of inversion of replication origin. All phylogenetic analyses consistently placed Dermaptera as the sister to Plecoptera, leaving them as the most basal lineage of Polyneoptera or sister to Ephemeroptera, and placed Odonata consistently as the most basal lineage of the Pterygota.
authors.affiliation: College of Agriculture & Life Sciences, Chonnam National University, Gwangju, Republic of Korea.
authors.forename: Xinlong
authors.initials: X
authors.lastname: Wan
authors.forename: Man Il
authors.initials: MI
authors.lastname: Kim
authors.forename: Min Jee
authors.initials: MJ
authors.lastname: Kim
authors.forename: Iksoo
authors.initials: I
authors.lastname: Kim
mesh_terms: D020856:AT Rich Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D021901:DNA, Intergenic / Q000235:genetics; D023061:Gene Order / Q000235:genetics; D050259:Genes, Mitochondrial / Q000235:genetics; D049750:Genome, Insect / Q000235:genetics*; D054629:Genome, Mitochondrial / Q000235:genetics*; D007313:Insecta / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D012343:RNA, Transfer / Q000235:genetics; D020080:Tandem Repeat Sequences / Q000235:genetics
chemical_list: D021901:DNA, Intergenic; D012343:RNA, Transfer