Origin, Spread and Demography of the Mycobacterium tuberculosis Complex
Figure 5
M. tuberculosis evolutionary scenario (out of Mesopotamia).
The main migrations events are numbered and correspond to: 1, M. prototuberculosis, the ancestor of the MTBC, this bacterium reached the Fertile Crescent some 40,000 years ago by sea or land; 2 and 3, two distinct basal lineages arose, EAI and LAM and spread out of Mesopotamia some 10, 000 years ago; 4, 5 and 6, later on (8–5000 years ago) derived populations from clade 1 followed main human migration patterns to Africa, Asia and Europe, giving rise to locally adapted tubercle strains and further diversifications. Note that the depicted borders are “artificial” and are used for the demonstration. Global movements and intercontinental exchanges tend to blur this phylogenetic signal though strong enough to be detected nowadays.