title: Rickettsiae and Chlamydiae: evidence of horizontal gene transfer and gene exchange.
mesh_terms: D002689:Chlamydia / Q000201:enzymology / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D000226:Mitochondrial ADP, ATP Translocases / Q000235:genetics; D010802:Phylogeny; D012281:Rickettsia / Q000737:chemistry* / Q000201:enzymology