Figure 4. En-Bloc Gene Transfer.

Phylogenetic trees for five consecutive genes in M. massiliensis illustrating lateral gene transfer with α-proteobacteria. Genes are labeled according to their names in the Kegg database, followed by the environmental category of the organism. The gene order is conserved among the three species, except for OppA, duplicated in B. japonicum and R. palustris. In this tree, gene names are colored according to the following code: M. massiliensis, blue; α-proteobacteria, yellow; β-proteobacteria, red; γ-proteobacteria, green; and others, black. The trees were built using a maximum likelihood substitution model and midpoint rooting.