Ancient DNA reveals genetic legacy of pandemics in the Americas

Geneticists are exploring how disease introduced by European colonists shaped the evolution of indigenous peoples of the Americas

Prehistoric America was not a disease-free utopia. Tuberculosis, treponemal disease, Chagas disease, and many other pathogens were endemic to populations in different regions of the continent. But the "Columbian Exchange" beginning in 1492 introduced new pathogens to American populations, including smallpox, measles, influenza, and yellow fever. This introduction had devastating consequences for tribes. In some places, death from infectious disease resulted in the depopulation of entire regions, leading to the collapse of social, economic, and political institutions, and the loss of many traditional cultural practices and ways of life.

Understanding the dynamics of these pandemics is critically important in order to learn how they may have shaped the genetic diversity of contemporary Native American communities, potentially giving insights into the genetic underpinnings of diseases present in a higher frequency in some populations than elsewhere. More broadly, documenting the historical effects of the introduction of novel pathogens can give insights into the evolution of host-pathogen relationships. These insights are potentially useful for responding to future outbreaks of emerging infectious diseases.