Fig. 3.—

Chlamydiales order, plasmids, and type IV secretion system. The left panel represents a neighbor joining tree of bacteria belonging to the order Chlamydiales, whose genome sequences are available, based on four conserved proteins (DnaA, FtsK, HemL, and FabI). The presence of a plasmid in each strain is represented by a small circular DNA molecule and the draft genomes with no described plasmid are indicated by a question mark as plasmids may be hidden among the numerous contigs. Orange ovals indicate the presence of a conjugative tra operon on the plasmid or in the bacterial chromosome. The right panel shows the conservation of the type IV secretion system tra operon and the surrounding genes. Pac: P. acanthamoebae, Nsp: Neochlamydia sp., Rma: R. massiliensis, Pna: Pr. naegleriophila, Pam: Pr. amoebophila, Pac HS-T3: Parachlamydiaceae bacterium HS-T3, Wch: Waddlia chondrophila, Cse: Criblamydia sequanensis, Ela: Estrella lausannensis, and Sne: Simkania negevensis.