The paradoxes of Mycobacterium tuberculosis molecular evolution and consequences for the inference of tuberculosis emergence date.

The date of Mycobacterium tuberculosis complex emergence has been the subject of long debates. New studies joining archaeological efforts with sequencing methods raise high hopes for solving whether this emergence is closer to 70,000 or to 6000 years before present. Inferring the date of emergence of this pathogen based on sequence data requires a molecular clock.