The species of the Mycobacterium tuberculosis Complex (MTBC)—M. tuberculosis, M. africanum, M. bovis, M. caprae, M. microti, and M. pinnipedii—are very closely related. In this webinar, we will discuss the techniques used to examine the MTBC in order to unravel this taxonomic mystery. Using phylogenomic techniques to compare the type strains of these species, we discovered that all of these “species” are, in fact, M. tuberculosis. We further examined all the strains deposited in GenBank under those species names and found all of them to be strains of M. tuberculosis. All known strains of three other putative MTBC members (“M. canettii”, “M. mungi”, and “M. orygis”) were similarly shown to be strain of M. tuberculosis. We have recently published a paper in the International Journal of Systematic and Evolutionary Microbiology officially unifying the previously separate MTBC species as M. tuberculosis.