Phylogenetic positions of the endosymbionts of two volvocalean species.

<p>The tree was inferred by the PhyML method (TrN+GAMMA+I model) based on 47 16 S <i>r</i>RNA gene sequences from bacteria, endosymbionts of (En) eukaryotic hosts, and environmental samples related to the family Rickettsiaceae. The sequences determined in this study are indicated by boldface. Bootstrap values (≥50%) of PhyML, ML (by PAUP*), and MP are indicated to the left, middle, and right of the nodes, respectively. The scale bar shows 0.05 nucleotide substitutions per position. Sequences belonging to the family Holosporaceae were designated as the outgroup. Accession numbers of sequences are shown in supporting information (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031749#pone.0031749.s010" target="_blank">Table S1</a>). The hydra group refers to Weinert et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031749#pone.0031749-Weinert1" target="_blank">[14]</a>.