Ancient DNA Shows Plague Killed Siberian Hunter-Gatherers 5,500 Years Ago

An international team sequenced ancient DNA from teeth recovered at four burial grounds around Lake Baikal in East Siberia, identifying Yersinia pestis in 18 of 46 tested individuals—about 40 percent. Radiocarbon dating places the infections around 5,500 years ago, predating agriculture and urban settlements. The prehistoric plague strains possessed a superantigen gene not seen in later historic variants, likely provoking severe immune reactions.

Archaeologists noted a disproportionate number of children among the dead, and some graves held siblings or parents with offspring, implying rapid, family-wide transmission. The findings challenge the view that early plague was mild and suggest that even without flea vectors, the disease could cause deadly outbreaks in small, mobile populations. Researchers propose that contact with infected marmots, which still harbor plague, may have sparked these ancient epidemics.