www.nature.com When the Black Death swept through northern Africa and Eurasia in the mid-fourteenth century, it killed up to half of the human populations there, reshaped history — and potentially changed the course of human evolution.
A study published on 19 October in Nature1 suggests that lingering scars from the bubonic plague, which was caused by the bacterium Yersinia pestis, can be found in genes involved in the modern human immune system. Four DNA variants in particular seem to have become more common after the Black Death, and might have contributed to survival.
But the protection afforded by those variants could have come at a cost: today, two of them are associated with an increased risk of autoimmune disorders, such as Crohn’s disease and rheumatoid arthritis…
