title: Phylogenetic placement of the Spirosomaceae.
abstract: Comparative analysis of 16S rRNA sequences shows that the family Spirosomaceae belongs within the eubacterial phylum defined by the flavobacteria and bacteriodes.  Its constituent genera, Spirosoma, Flectobacillus, and Runella form a monophyletic grouping therein.  The phylogenetic assignment is based not only upon evolutionary distance analysis, but also upon sequence signatures and higher order structural synapomorphies in 16S rRNA.  Another genus peripherally associated with the Spirosomaceae, Ancylobacter ("Microcyclus"), does not cluster with the flavobacteria and their relatives, but rather belongs to the alpha subdivision of the purple bacteria.
authors.affiliation: Department of Microbiology, University of Illinois, Urbana 61801, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Woese
authors.forename: S
authors.initials: S
authors.lastname: Maloy
authors.forename: L
authors.initials: L
authors.lastname: Mandelco
authors.forename: H D
authors.initials: HD
authors.lastname: Raj
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D010802:Phylogeny; D012329:RNA, Bacterial / Q000145:classification / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000145:classification / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S