Protein maximum likelihood tree of alcohol dehydrogenase E ( adhE gene). Phylogenetic tree based on 796 unambiguously aligned aa positions of the alcohol dehydrogenase E protein sequences. The grey boxes A and B indicate strongly separated groups which include eukaryotic sequences. The tree is arbitrarily rooted. Details about the phylogenetic analyses are found in the Methods section and Additional File 2. Labelling as in Figure 2.