M. kansasii and M. marinum are two environmental mycobacteria closely related to M. tuberculosis genome. They are used as model of M. tuberculosis, the etiological agent of human tuberculosis, but “missing links” still exist in the evolution of M. tuberculosis.
Recently, new mycobacteria were isolated from patients and revealed more similarities with M. tuberculosis than the two previously used models. In a recent study, these new mycobacteria (M. decipiens, M. lacus, M. riyadhense and M. shinjukuense) seem to represent the “missing links” between M. tuberculosis and other environmental mycobacteria.
The genome comparison of the four new mycobacteria and M. tuberculosis could help to elucidate the molecular factors responsible for the important evolutionary success of M. tuberculosis as a pathogen.
