Phylogenetic tree of Midichloria spp. 16S rDNA gene sequences. Example of a phylogenetic tree showing the positioning of the Midichloria spp. 16S rDNA gene sequences generated from mammalian hosts (bold) relative to those generated in previous studies from ticks. In addition to sequences attributable to the genus Midichloria, other from the genus Lariskella have been included as outgroups. Names at the terminal nodes are those of the host organisms (mammalians, ticks, and other arthropod species in the case of the genus Lariskella). The tree was built using the Neighbor-joining method after Kimura two-parameters corrections, with the insertions/deletions not taken into account. Numbers at the nodes are the bootstrap confidence values; the scale bar indicates the number of substitutions per nucleotide. Accession numbers of the sequences are indicated at the terminal nodes. When multiple identical sequences were obtained from blood specimens of the same mammalian species, only one sequence was deposited in the data bases; in these cases, the number of specimens displaying identical sequences is given in parenthesis.