Maximum likelihood tree of paraslipin proteins. The phylogeny was based on a 272 amino acid alignment. Numbers on the branches show percentage bootstrap occurrence of nodes in 100 replicates. Only values > 70 are shown. The scale bar indicates the number of amino acid substitutions per site. indicates the clade uniting Chlorobi, Gammaproteobacteria and Spirochetes with two parallel phylogenies. Note the position of Rickettsiales as the sister group to the eukaryotic clade. Accession numbers available in Additional file 2.