title: Population genomics of early events in the ecological differentiation of bacteria.
abstract: Genetic exchange is common among bacteria, but its effect on population diversity during ecological differentiation remains controversial. A fundamental question is whether advantageous mutations lead to selection of clonal genomes or, as in sexual eukaryotes, sweep through populations on their own. Here, we show that in two recently diverged populations of ocean bacteria, ecological differentiation has occurred akin to a sexual mechanism: A few genome regions have swept through subpopulations in a habitat-specific manner, accompanied by gradual separation of gene pools as evidenced by increased habitat specificity of the most recent recombinations. These findings reconcile previous, seemingly contradictory empirical observations of the genetic structure of bacterial populations and point to a more unified process of differentiation in bacteria and sexual eukaryotes than previously thought.
authors.affiliation: Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: B Jesse
authors.initials: BJ
authors.lastname: Shapiro
authors.forename: Jonathan
authors.initials: J
authors.lastname: Friedman
authors.forename: Otto X
authors.initials: OX
authors.lastname: Cordero
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Preheim
authors.forename: Sonia C
authors.initials: SC
authors.lastname: Timberlake
authors.forename: Gitta
authors.initials: G
authors.lastname: Szabó
authors.forename: Martin F
authors.initials: MF
authors.lastname: Polz
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Alm
mesh_terms: D002876:Chromosomes, Bacterial / Q000235:genetics; D017753:Ecosystem; D019143:Evolution, Molecular; D051456:Gene Flow; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D014644:Genetic Variation; D016680:Genome, Bacterial; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009792:Oceans and Seas; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D012623:Seawater / Q000382:microbiology*; D012641:Selection, Genetic; D014733:Vibrio / Q000145:classification / Q000235:genetics*