title: Phylogenomics of the reproductive parasite Wolbachia pipientis wMel: a streamlined genome overrun by mobile genetic elements.
abstract: The complete sequence of the 1,267,782 bp genome of Wolbachia pipientis wMel, an obligate intracellular bacteria of Drosophila melanogaster, has been determined. Wolbachia, which are found in a variety of invertebrate species, are of great interest due to their diverse interactions with different hosts, which range from many forms of reproductive parasitism to mutualistic symbioses. Analysis of the wMel genome, in particular phylogenomic comparisons with other intracellular bacteria, has revealed many insights into the biology and evolution of wMel and Wolbachia in general. For example, the wMel genome is unique among sequenced obligate intracellular species in both being highly streamlined and containing very high levels of repetitive DNA and mobile DNA elements. This observation, coupled with multiple evolutionary reconstructions, suggests that natural selection is somewhat inefficient in wMel, most likely owing to the occurrence of repeated population bottlenecks. Genome analysis predicts many metabolic differences with the closely related Rickettsia species, including the presence of intact glycolysis and purine synthesis, which may compensate for an inability to obtain ATP directly from its host, as Rickettsia can. Other discoveries include the apparent inability of wMel to synthesize lipopolysaccharide and the presence of the most genes encoding proteins with ankyrin repeat domains of any prokaryotic genome yet sequenced. Despite the ability of wMel to infect the germline of its host, we find no evidence for either recent lateral gene transfer between wMel and D. melanogaster or older transfers between Wolbachia and any host. Evolutionary analysis further supports the hypothesis that mitochondria share a common ancestor with the alpha-Proteobacteria, but shows little support for the grouping of mitochondria with species in the order Rickettsiales. With the availability of the complete genomes of both species and excellent genetic tools for the host, the wMel-D. melanogaster symbiosis is now an ideal system for studying the biology and evolution of Wolbachia infections.
authors.affiliation: The Institute for Genomic Research, Rockville, Maryland, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Wu
authors.forename: Ling V
authors.initials: LV
authors.lastname: Sun
authors.forename: Jessica
authors.initials: J
authors.lastname: Vamathevan
authors.forename: Markus
authors.initials: M
authors.lastname: Riegler
authors.forename: Robert
authors.initials: R
authors.lastname: Deboy
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Brownlie
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: McGraw
authors.forename: William
authors.initials: W
authors.lastname: Martin
authors.forename: Christian
authors.initials: C
authors.lastname: Esser
authors.forename: Nahal
authors.initials: N
authors.lastname: Ahmadinejad
authors.forename: Christian
authors.initials: C
authors.lastname: Wiegand
authors.forename: Ramana
authors.initials: R
authors.lastname: Madupu
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: Beanan
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Brinkac
authors.forename: Sean C
authors.initials: SC
authors.lastname: Daugherty
authors.forename: A Scott
authors.initials: AS
authors.lastname: Durkin
authors.forename: James F
authors.initials: JF
authors.lastname: Kolonay
authors.forename: William C
authors.initials: WC
authors.lastname: Nelson
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Mohamoud
authors.forename: Perris
authors.initials: P
authors.lastname: Lee
authors.forename: Kristi
authors.initials: K
authors.lastname: Berry
authors.forename: M Brook
authors.initials: MB
authors.lastname: Young
authors.forename: Teresa
authors.initials: T
authors.lastname: Utterback
authors.forename: Janice
authors.initials: J
authors.lastname: Weidman
authors.forename: William C
authors.initials: WC
authors.lastname: Nierman
authors.forename: Ian T
authors.initials: IT
authors.lastname: Paulsen
authors.forename: Karen E
authors.initials: KE
authors.lastname: Nelson
authors.forename: Hervé
authors.initials: H
authors.lastname: Tettelin
authors.forename: Scott L
authors.initials: SL
authors.lastname: O'Neill
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Eisen
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D019070:Cell Lineage; D004247:DNA / Q000737:chemistry / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D004331:Drosophila melanogaster / Q000382:microbiology; D019143:Evolution, Molecular; D017353:Gene Deletion; D020440:Gene Duplication; D015723:Gene Library; D005798:Genes, Bacterial; D016678:Genome; D016680:Genome, Bacterial; D023281:Genomics / Q000379:methods*; D006019:Glycolysis; D020071:Interspersed Repetitive Sequences; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010271:Parasites; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary; D011687:Purines / Q000737:chemistry; D020577:Wolbachia / Q000235:genetics*
chemical_list: D017931:DNA Primers; D011687:Purines; D000255:Adenosine Triphosphate; D004247:DNA