title: An African origin for the intimate association between humans and Helicobacter pylori.
abstract: Infection of the stomach by Helicobacter pylori is ubiquitous among humans. However, although H. pylori strains from different geographic areas are associated with clear phylogeographic differentiation, the age of an association between these bacteria with humans remains highly controversial. Here we show, using sequences from a large data set of bacterial strains that, as in humans, genetic diversity in H. pylori decreases with geographic distance from east Africa, the cradle of modern humans. We also observe similar clines of genetic isolation by distance (IBD) for both H. pylori and its human host at a worldwide scale. Like humans, simulations indicate that H. pylori seems to have spread from east Africa around 58,000 yr ago. Even at more restricted geographic scales, where IBD tends to become blurred, principal component clines in H. pylori from Europe strongly resemble the classical clines for Europeans described by Cavalli-Sforza and colleagues. Taken together, our results establish that anatomically modern humans were already infected by H. pylori before their migrations from Africa and demonstrate that H. pylori has remained intimately associated with their human host populations ever since.
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
authors.forename: Bodo
authors.initials: B
authors.lastname: Linz
authors.affiliation: Theoretical and Molecular Population Genetics Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.
authors.forename: François
authors.initials: F
authors.lastname: Balloux
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
authors.forename: Yoshan
authors.initials: Y
authors.lastname: Moodley
authors.affiliation: Evolutionary Ecology Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Manica
authors.affiliation: Theoretical and Molecular Population Genetics Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
authors.forename: Philippe
authors.initials: P
authors.lastname: Roumagnac
authors.affiliation: Department of Statistics, University of Oxford, Oxford OX1 3SY, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Falush
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
authors.forename: Christiana
authors.initials: C
authors.lastname: Stamer
authors.affiliation: Génétique et Evolution des Maladies Infectieuses, UMR IRD-CNRS 2724, centre IRD de Montpellier, 911 Av. Agropolis, BP 64501, 34394 Montpellier Cedex 05, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Prugnolle
authors.affiliation: Department of Internal Medicine and Gastroenterology, University of Pretoria, South Africa.
authors.forename: Schalk W
authors.initials: SW
authors.lastname: van der Merwe
authors.affiliation: Department of Medicine-Gastroenterology, Baylor College of Medicine and Michael E. DeBakey VA Medical Center, Houston, TX 77030, U.S.A.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaoka
authors.affiliation: Department of Medicine-Gastroenterology, Baylor College of Medicine and Michael E. DeBakey VA Medical Center, Houston, TX 77030, U.S.A.
authors.forename: David Y
authors.initials: DY
authors.lastname: Graham
authors.affiliation: Department of Microbiology, Donostia Hospital, 20014 San Sebastian, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Perez-Trallero
authors.affiliation: Department of Laboratory Medicine, Lund University, SE22632 Lund, Sweden.
authors.forename: Torkel
authors.initials: T
authors.lastname: Wadstrom
authors.affiliation: Medizinische Hochschule Hannover, Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Suerbaum
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Achtman
mesh_terms: D000349:Africa / Q000453:epidemiology; D001208:Asia; D004641:Emigration and Immigration; D005060:Europe; D014644:Genetic Variation; D005843:Geography; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000502:physiology*; D049690:History, Ancient; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny