title: Origin, spread and demography of the Mycobacterium tuberculosis complex.
abstract: The evolutionary timing and spread of the Mycobacterium tuberculosis complex (MTBC), one of the most successful groups of bacterial pathogens, remains largely unknown. Here, using mycobacterial tandem repeat sequences as genetic markers, we show that the MTBC consists of two independent clades, one composed exclusively of M. tuberculosis lineages from humans and the other composed of both animal and human isolates. The latter also likely derived from a human pathogenic lineage, supporting the hypothesis of an original human host. Using Bayesian statistics and experimental data on the variability of the mycobacterial markers in infected patients, we estimated the age of the MTBC at 40,000 years, coinciding with the expansion of "modern" human populations out of Africa. Furthermore, coalescence analysis revealed a strong and recent demographic expansion in almost all M. tuberculosis lineages, which coincides with the human population explosion over the last two centuries. These findings thus unveil the dynamic dimension of the association between human host and pathogen populations.
authors.affiliation: Department of Biology, Lehrstuhl für Zoologie und Evolutionsbiologie, University of Konstanz, Konstanz, Germany. wirth@mnhn.fr
authors.forename: Thierry
authors.initials: T
authors.lastname: Wirth
authors.forename: Falk
authors.initials: F
authors.lastname: Hildebrand
authors.forename: Caroline
authors.initials: C
authors.lastname: Allix-Béguec
authors.forename: Florian
authors.initials: F
authors.lastname: Wölbeling
authors.forename: Tanja
authors.initials: T
authors.lastname: Kubica
authors.forename: Kristin
authors.initials: K
authors.lastname: Kremer
authors.forename: Dick
authors.initials: D
authors.lastname: van Soolingen
authors.forename: Sabine
authors.initials: S
authors.lastname: Rüsch-Gerdes
authors.forename: Camille
authors.initials: C
authors.lastname: Locht
authors.forename: Sylvain
authors.initials: S
authors.lastname: Brisse
authors.forename: Axel
authors.initials: A
authors.lastname: Meyer
authors.forename: Philip
authors.initials: P
authors.lastname: Supply
authors.forename: Stefan
authors.initials: S
authors.lastname: Niemann
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D014644:Genetic Variation; D006801:Humans; D018895:Microsatellite Repeats; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D010802:Phylogeny; D013045:Species Specificity; D015047:Zoonoses