Scientists from France, Sweden, and Denmark have identified an ancient strain of plague bacteria (Yersinia pestis) in the 5,000-year-old DNA samples extracted from the human remains found in a mass grave. According to the researchers, who published their study’s result on December 6th in the journal Cell, this plague strain is the closest one to the genetic origin of the disease.
“Plague is maybe one of the deadliest bacteria that has ever existed for humans. And if you think of the word ‘plague,’ it can mean this infection by Y. pestis, but because of the trauma plague has caused in our history, it’s also come to refer more generally to any epidemic. The kind of analyses we do here let us go back through time and look at how this pathogen that’s had such a huge effect on us evolved,” explained Simon Rasmussen from the University of Copenhagen.
Rasmussen and his co-workers analyzed all the publicly available data on the genetics of ancient humans and compared ancient strains of plague with modern-day ones.
Ancient Strain Of Plague May Have Caused The Decline Of Neolithic Europeans
About 5,000 years ago, mega-settlements of 10,000-20,000 inhabitants were common across Europe. At the same time, the first major human migrations happened. The scientists suggest that the migrators have brought plague with them. In about the same period, as researchers reported, the settlements of the Neolithic Europeans began to decline.
“These mega-settlements were the largest settlements in Europe at that time, ten times bigger than anything else. They had people, animals, and stored food close together, and, likely, very poor sanitation. That’s the textbook example of what you need to evolve new pathogens,” said Rasmussen.
“If plague evolved in the mega-settlements, then when people started dying from it, the settlements would have been abandoned and destroyed. That is exactly what was observed in these settlements after 5,500 years ago. The plague would also have started migrating along all the trade routes made possible by wheeled transport, which had rapidly expanded throughout Europe in this period,” the researcher added.