Complete mitochondrial genomes of two Phoretic mites (Parasitidae: Poecilochirus) on burying beetle: Genome characterization and phylogenetic analysis

A pair of intriguing phoretic instances are the burying beetle and Poecilochirus mites. Their interaction is environment-dependent and can be either mutualistic or antagonistic hostile depending on various biological and physical circumstances. In this study, we sequenced the complete mitogenomes of two Poecilochirus mite species, P. davydovae and P. mrciaki, which are associated with burying beetles, using Illumina HiSeq sequencing technology. Each mitochondrial genome comprised 37 typical genes, including 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one control region (CR). The size of these mitogenomes were determined to be 14,489 bp and 14,517 bp, respectively. These two mitochondrial genomes contain a notable AT bias in their nucleotide composition, with positive AT and negative GC skews in the deflection index of mitochondrial genomes, and a unique incomplete stop codon T- in both protein-coding genes. The DHU arm of tRNA-S1 (AGN) only forms a simple loop structure, while the secondary structures of 21 tRNA genes in both species showed the conventional cloverleaf structures, like those of most metazoans. The phylogenetic tree of Gamasina was constructed using Maximum likelihood and Bayesian inference based on two rRNA genes and 13 PCGs. Based on the existing data, the Parasitidae forms a monophyletic, and Poecilochirus and Parasitus are closely related, possibly belonging to the same genus.