Complete mitochondrial genomes of Anopheles stephensi and An. dirus and comparative evolutionary mitochondriomics of 50 mosquitoes

To better understand the phylogeny and evolution of mosquitoes, the complete mitochondrial genome (mitogenome) of Anopheles stephensi and An. dirus were sequenced and annotated, and a total of 50 mosquito mitogenomes were comparatively analyzed. The complete mitogenome of An. stephensi and An. dirus is 1,5371 bp and 1,5406 bp long, respectively. The main features of the 50 mosquito mitogenomes are conservative: 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes, positive AT-skew and negative GC-skew. The gene order trnA-trnR in ancestral insects is rearranged. All tRNA genes have the typical clover leaf secondary structure but tRNA (Ser). The control regions are highly variable in size. PCGs show signals of purifying selection, but evidence for positive selection in ND2, ND4 and ND6 is found. Bayesian and Maximum Likelihood phylogenetic analyses based on all PCG nucleotides produce an identical tree topology and strongly support the monophyly of subgenera Cellia, Anopheles, Keterszia and Nyssorhynchus, the sister relationship of the subgenera Nyssorhynchus and Keterszia, and Cellia and Anopheles. The most recent ancestor of the genus Anopheles and Culicini + Aedini exited ~145 Mya ago. This is the first comprehensive study of mosquito mitogenomes, which are effective for mosquito phylogeny at various taxonomic levels.