The full-length mitochondrial rDNA sequence of Tyrophagus longior (Astigmata: Acaridae) and phylogeny of astigmatid mites based on mitochondrial rDNA sequences

Mites of the genus Tyrophagus are economically important as they are polyphagous stored product pests and cause medically allergic reactions to human. Considering that examining the phylogenetic relationship among Astigmata species might help to understand their evolutionary process, we sequenced and analyzed the mitochondrial (mt) rDNA of the Tyrophagus longior and compared with those of six other astigmatid mites, as well as assessed the phylogenetic relationship among astigmatid species based on the complete mt rDNA sequences. Sequence analysis showed that the mt rDNA sequences of seven Astigmata species have high A + T contents (average value: 72.0% for 12S rRNA and 72.4% for 16S rRNA, respectively). The genetic distance and transition/transversion (TS/TV) of the seven Astigmata species reached interspecies level. In addition, the predicted stem-loop secondary structure of T. longior mt rDNA closely resembled those of other reported acariform mites. Finally, phylogenetic analyses based on complete sequences of 12S rRNA and 16S rRNA genes revealed that a close relationship between the families Acaridae and Pyroglyphidae, and supported the monophyly of the Acaridae as well as the Astigmata. These results are consistent with traditional classifications. Therefore, the mt rRNA genes are suitable for inferring phylogenetic relationship among astigmatid mites in this study, although the differentiation among the seven astigmata species has approached interspecies level.