An African origin for the intimate association between humans and Helicobacter pylori.
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.
Linz
Bodo
B
Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
Balloux
François
F
Theoretical and Molecular Population Genetics Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.
Moodley
Yoshan
Y
Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
Manica
Andrea
A
Evolutionary Ecology Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
Liu
Hua
H
Theoretical and Molecular Population Genetics Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK.
Roumagnac
Philippe
P
Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
Falush
Daniel
D
Department of Statistics, University of Oxford, Oxford OX1 3SY, UK.
Stamer
Christiana
C
Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
Prugnolle
Franck
F
Génétique et Evolution des Maladies Infectieuses, UMR IRD-CNRS 2724, centre IRD de Montpellier, 911 Av. Agropolis, BP 64501, 34394 Montpellier Cedex 05, France.
van der Merwe
Schalk W
SW
Department of Internal Medicine and Gastroenterology, University of Pretoria, South Africa.
Yamaoka
Yoshio
Y
Department of Medicine-Gastroenterology, Baylor College of Medicine and Michael E. DeBakey VA Medical Center, Houston, TX 77030, U.S.A.
Graham
David Y
DY
Department of Medicine-Gastroenterology, Baylor College of Medicine and Michael E. DeBakey VA Medical Center, Houston, TX 77030, U.S.A.
Perez-Trallero
Emilio
E
Department of Microbiology, Donostia Hospital, 20014 San Sebastian, Spain.
Wadstrom
Torkel
T
Department of Laboratory Medicine, Lund University, SE22632 Lund, Sweden.
Suerbaum
Sebastian
S
Medizinische Hochschule Hannover, Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
Achtman
Mark
M
Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany.
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