Background: The family Hoplopleuridae contains at least 183 species of blood-sucking lice, which widely parasitize both mice and rats. Fragmented mitochondrial (mt) genomes have been reported in two rat lice (Hoplopleura kitti and Hoplopleura akanezumi) from this family, but some minichromosomes were unidentified in their mt genomes.
Methods: We sequenced the mt genome of rat louse Hoplopleura sp. with an Illumina platform and compared its mt genome organization with Hoplopleura kitti and Hoplopleura akanezumi.
Results: Fragmented mt genome of the rat louse Hoplopleura sp. contains 37 genes which are on 12 circular mt minichromosomes. Each mt minichromosome is 1.8-2.7 kb long, which contains 1-5 genes and one large non-coding region. The gene content and arrangement of three mt minichromosomes of Hoplopleura sp. and Hoplopleura kitti are different from that of the three mt minichromosomes of Hoplopleura akanezumi. Phylogenetic analyses based on the deduced amino acid sequences of the eight protein-coding genes showed that the Hoplopleura sp. was more closely related to Hoplopleura akanezumi than to Hoplopleura kitti, and then they formed a monophyletic group.
Conclusions: Comparison among the three rat lice revealed variation in the composition of mt minichromosomes within the genus Hoplopleura. Hoplopleura sp. is the first species from the family Hoplopleuridae for which a complete fragmented mt genome has been sequenced. The new data provides useful genetic markers for studying the population genetics, molecular systematics and phylogenetics of blood-sucking lice.