“It is like finding the place where all the strains come together, like with coronavirus where we have Alpha, Delta, Omicron all coming from this strain in Wuhan," says Johannes Krause, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who co-led the study, published in Nature.
Was China the epicentre for Black Death?
Several years ago, Philip Slavin, an economic and environmental historian at the University of Stirling, UK, and a co-lead author of the study, suggested the disease's emergence might be linked to an unusual surge of deaths in a town in Central Asia in 1338-1339.
The cemeteries, known as Kara-Djigach and Burana, held an unusually high number of tombstones dated to 1338 and 1339, ten of which made explicit reference to a pestilence. “When you have one or two years with excess mortality, it means something funny is going on there," Slavin had said.
Drawing from the same study, scientists examined DNA from bodies found there. They found genetic fingerprints of the bacterium Yersinia pestis in individuals who had been buried with tombstones.
A pair of full Y. pestis genomes gleaned from the data showed that the bacteria were direct ancestors of strains linked to the Black Death, including a Y. pestis sample from a person who died in London that Krause’s team sequenced in 2011.
“We found that the ancient strains from Kyrgyzstan are positioned exactly at the node of this massive diversification event," said Maria Spyrou, a researcher on disease history at the University of Tuebingen in Germany and lead author of the report. “In other words, we found the Black Death’s source strain and we even know its exact date (1338)."
This study is important: scientists said
Sharon DeWitte, a biological anthropologist at the University of South Carolina who was not involved in the study, said it was exciting to have the DNA evidence to back up the previous theory that the disease emerged in Central Asia.
“This study is important because the very precisely dated burials allow for a direct study of the strain as it existed at the time of the initial emergence of the Black Death," she said, as quoted by news agency AP.
