Novel mitochondrial genes and gene reannotation: conservation of gene arrangements among available astigmatid mites

Abstract Background Mitochondrial genomes (mitogenomes) of metazoans typically contain 37 genes, comprising 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. To date, complete mitogenome sequences of 15 species of Astigmatina are available, and they present variation in a number of features, such as gene arrangements, tRNA unconventional secondary structures, and the number and internal structures of control regions. Furthermore, 11 astigmatid mites from six superfamilies share the same gene arrangement. Two available species from the genus Histiostoma reportedly have different mitochondrial (mt) tRNA gene arrangements. Results We sequenced the mitogenomes of Lepidoglyphus destructor and Gohieria fusca, both from the superfamily Glycyphagoidea (Astigmatina). In total, 37 mt genes were identified in the two Glycyphagoidea species. Based on AT content and stem-loop structures, we divided the largest non-coding regions (LNRs) in L. destructor and G. fusca into two domains, respectively. The novel feature of two domains for the LNR was also found in Acalvolia sp. (Astigmatina, Hemisarcoptoidea). Using MITOS 2, tRNAScan, ARWEN, and manual approaches, we reannotated the mitogenomes of Histiostoma blomquisti, H. feroniarum, and Trouessartia rubecula. We reannotated six tRNA genes in H. blomquisti and four tRNA genes in H. feroniarum. We were able to identify all of the mt tRNA genes that were reported as lost in Tr. rubecula. The phylogenetic relationships found in our study were fairly consistent with previous studies of astigmatid mites phylogeny. Within Astigmatina, Glycyphagoidea was recovered as a monophyletic group. Conclusions A novel feature of the LNR was found in L. destructor, G. fusca and Acalvolia sp. (Astigmatina, Hemisarcoptoidea). This feature was not found in other available Astigmatina mitochondrial sequences. In the current study, most available astigmatid mitochondrial genomes shared the same consistent gene arrangement that could be the potential ancestral pattern in Astigmatina.