In their study published in
Nature, an international team of researchers analyzed ancient DNA from
human remains as well as historical and
archaeological data from two sites that were found to contain "pestilence" inscriptions. The team's first results were very encouraging, as DNA from the
plague bacterium, Yersinia pestis, was identified in individuals with the year 1338 inscribed on their tombstones. "We could finally show that the epidemic mentioned on the tombstones was indeed caused by plague," says Phil Slavin, one of the senior authors of the study and historian at the University of Sterling, U.K.
But could this have been the origin of the Black Death? Researchers have previously associated the Black Death's initiation with a massive diversification of plague strains, a so-called Big Bang event of plague diversity. But the exact date of this event could not be precisely estimated, and was thought to have happened sometime between the 10th and 14th centuries.
The team now pieced together complete ancient plague genomes from the sites in Kyrgyzstan and investigated how they might relate with this Big Bang event. "We found that the ancient strains from Kyrgyzstan are positioned exactly at the node of this massive diversification event. In other words, we found the Black Death's source strain and we even know its exact date [meaning the year 1338]", says Maria Spyrou, lead author and researcher at the University of Tübingen.