City immunity to TB
23rd September 2010
Mark Thomas in collaboration with Ian Barnes et al published the paper Ancient Urbanization Predicts Genetic Resistance to Tuberculosis in The Journal of Evolution, which offered strong statistical evidence to support the hypothesis that in ancient cities, high population density would have contributed to a strong breeding ground for the spread of diseases such as TB, which in turn would have created a stong selection pressure on a genetic mutation which protects from TB.
"Population density seems to play an important role in shaping so many aspects of our species. It was a vital factor in our species maintaining the complex skills and culture that distinguish us from other primates. It drove many of the genetic differences we see today between different populations from around the world. And now, it seems, it also influenced how infectious diseases spread in the past and how we evolved to resist those diseases." -Mark Thomas