I joined the group headed by Olivier Neyrolles, at the IPBS in Toulouse in 2011. I am investigating the role of genes acquired by horizontal gene transfer in the evolution of the ancestor of Mycobacterium tuberculosis (Mtb). Our working hypothesis is that such genes have contributed to the evolution of the non-pathogenic ancestor of Mtb towards the major human pathogen we are facing nowadays, by improving the fitness of the bacterium upon infection of its host.