title: Evolution of photosynthetic prokaryotes: a maximum-likelihood mapping approach.
abstract: Reconstructing the early evolution of photosynthesis has been guided in part by the geological record, but the complexity and great antiquity of these early events require molecular genetic techniques as the primary tools of inference. Recent genome sequencing efforts have made whole genome data available from representatives of each of the five phyla of bacteria with photosynthetic members, allowing extensive phylogenetic comparisons of these organisms. Here, we have undertaken whole genome comparisons using maximum likelihood to compare 527 unique sets of orthologous genes from all five photosynthetic phyla. Substantiating recent whole genome analyses of other prokaryotes, our results indicate that horizontal gene transfer (HGT) has played a significant part in the evolution of these organisms, resulting in genomes with mosaic evolutionary histories. A small plurality phylogenetic signal was observed, which may be a core of remnant genes not subject to HGT, or may result from a propensity for gene exchange between two or more of the photosynthetic organisms compared.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Raymond
authors.forename: Olga
authors.initials: O
authors.lastname: Zhaxybayeva
authors.forename: J Peter
authors.initials: JP
authors.lastname: Gogarten
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D016678:Genome; D016013:Likelihood Functions; D010788:Photosynthesis / Q000235:genetics*; D010802:Phylogeny; D011387:Prokaryotic Cells / Q000502:physiology*