Abstract: Tuberculosis (TB) has long been a scourge of humans, as well as other animals. Here, I will discuss how ancient DNA allows us to examine the history of Mycobacterium tuberculosis and related strains in the M. tuberculosis complex (MTBC) which cause the disease. In particular, I will focus on patterns of pathogen exchange before and after the “Age of Exploration/Colonization” and discuss ways that TB may have adapted to humans and other animals. We previously analyzed MTBC genomes from three 1000-year old skeletal TB cases from coastal Peru and found that they are closely related to strains in sea mammals (specifically Southern Hemisphere pinnipeds). However, it is unclear whether these pinniped-derived MTBC strains spread to inland parts of South America as well as North America by human-to-human transmission or whether different strains spread into the Americas via another route. After contact, European TB strains were introduced, apparently replacing pre-contact strains but the timing and extent of this is unknown. New analyses show evidence for the spread of pinniped-derived MTBC strains to people in non-coastal areas, likely due to human-to-human transmission. Our data also suggest that modern American strain distributions reflect the introduction of strains commonly circulating in the source areas of colonists.

Short Bio: Anne Stone is Regents’ Professor in the School of Human Evolution and Social Change at the Arizona State University. Currently, her research focuses on population history and understanding how humans and the great apes other primates have adapted to their environments, including their disease and dietary environments. This includes: (a) Native American population history, (b) the evolutionary history of the Great Apes, and (c) understanding the evolutionary history of mycobacteria (specifically the causative agents of tuberculosis and leprosy). Stone has been a Fulbright Fellow (1992-93), a NIH NRSA postdoctoral fellow (1997-1998), and a Kavli Scholar (2007). She is a fellow of the American Association for the Advancement of Science (2011) and a member of the National Academy of Sciences (2016). Stone currently serves as a senior editor of Molecular Biology and Evolution.