title: Discovery of a free-living chlorophyll d-producing cyanobacterium with a hybrid proteobacterial/cyanobacterial small-subunit rRNA gene.
abstract: Chlorophyll d-producing cyanobacteria are a recently described group of phototrophic bacteria that is a major focus of photosynthesis research, previously known only from marine environments in symbiosis with eukaryotes. We have discovered a free-living member of this group from a eutrophic hypersaline lake. Phylogenetic analyses indicated these strains are closely related to each other but not to prochlorophyte cyanobacteria that also use an alternative form of chlorophyll as the major light-harvesting pigment. We have also demonstrated that these bacteria acquired a fragment of the small-subunit rRNA gene encoding a conserved hairpin in the bacterial ribosome from a proteobacterial donor at least 10 million years before the present. Thus, our most widely used phylogenetic marker can be a mosaic of sequence fragments with widely divergent evolutionary histories.
authors.affiliation: Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA. scott.miller@mso.umt.edu
authors.forename: Scott R
authors.initials: SR
authors.lastname: Miller
authors.forename: Sunny
authors.initials: S
authors.lastname: Augustine
authors.forename: Tien Le
authors.initials: TL
authors.lastname: Olson
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
authors.forename: Jeanne
authors.initials: J
authors.lastname: Selker
authors.forename: A Michelle
authors.initials: AM
authors.lastname: Wood
mesh_terms: D001483:Base Sequence; D002678:Chimera; D002734:Chlorophyll; D017124:Conserved Sequence; D000458:Cyanobacteria / Q000235:genetics*; D019143:Evolution, Molecular; D020459:Genes, rRNA; D005819:Genetic Markers; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D020560:Proteobacteria / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D005819:Genetic Markers; D002734:Chlorophyll; C107509:chlorophyll d