title: A small microbial genome: the end of a long symbiotic relationship?
abstract: Intracellular bacteria are characterized by genome reduction. The 422,434-base pair genome of Buchnera aphidicola BCc, primary endosymbiont of the aphid Cinara cedri, is approximately 200 kilobases smaller than the previously sequenced B. aphidicola genomes. B. aphidicola BCc has lost most metabolic functions, including the ability to synthesize the essential amino acid tryptophan and riboflavin. In addition, most retained genes are evolving rapidly. Possibly, B. aphidicola BCc is losing its symbiotic capacity and is being complemented (and might be replaced) by the highly abundant coexisting secondary symbiont.
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Apartado Postal 22085, 46071 València, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Pérez-Brocal
authors.forename: Rosario
authors.initials: R
authors.lastname: Gil
authors.forename: Silvia
authors.initials: S
authors.lastname: Ramos
authors.forename: Araceli
authors.initials: A
authors.lastname: Lamelas
authors.forename: Marina
authors.initials: M
authors.lastname: Postigo
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Michelena
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Silva
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
authors.forename: Amparo
authors.initials: A
authors.lastname: Latorre
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis; D000818:Animals; D001042:Aphids / Q000382:microbiology* / Q000502:physiology; D020029:Base Pairing; D020635:Buchnera / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002876:Chromosomes, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D012705:Serratia / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013559:Symbiosis; D014364:Tryptophan / Q000096:biosynthesis
chemical_list: D000596:Amino Acids; D014364:Tryptophan