Partial phylogenetic trees of four marine adaptation genes. (A) Na+/bile acid symporter, (B) Na+/Ca+2 exchanger, (C) PstS of the high affinity phosphate transporter, and (D) LivK from the branched chain amino acid transporter. Note: deep branches within the Actinobacteria are incongruent with the species phylogeny. Branches and species are colored as in Figure 2. See Additional file 4 for detailed tree parameters.