Origin of Black Death Gets Traced in Central Eurasia through Ancient DNA

Known as the Plague, the disease is caused by the bacteria Yersinia pestis which is usually found in small mammals like rodents and their fleas.

The plague is an ancient disease with genetic evidence of existence since the Neolithic and Bronze Ages. However, it was only during the reign of Byzantine emperor Justinian I in 600 CE that a bubonic outbreak was documented.

Then came the Black Death that wiped out 60% of the population of western Eurasia. It was such a terrible disease. The Italian poet Giovanni Boccaccio described it as follows: “In men and women alike, at the beginning of the malady, certain swellings, either on the groin or under the armpits . . . waxed to the bigness of a common apple, others to the size of an egg, some more and some less, and these the vulgar named plague-boils.”

Out of the boils, blood and pus came, followed by other dreadful symptoms such as fever, chills, diarrhea, vomiting, excruciating pain . . . then, death.

It is no wonder that with the emergence of the coronavirus pandemic, the interest in the origin of the Black Death has intensified. The knowledge could help the world in dealing more effectively with extremely contagious diseases, whether bacterial or viral in origin. And, of course, there is a major concern that the plague could be used as a weapon of biological warfare. In the 14th century, Kipchak Khan Janibeg tried to use it against Crimea after the disease annihilated his army. In World War II, Japan experimented with it in their Manchurian research facilities and used it several times against China.

Now a team of experts has uncovered the origin of the Black Death through ancient DNA from 14th-century graves in Kyrgyzstan. Philip Slavin, an economic and environmental historian at the University of Stirling in the United Kingdom and a co-lead author of the study, became intrigued by documents pertaining to the cemeteries of Kara-Djigach and Burana, where there was a detailed reference to a pestilence.

Suspecting that the records were connected with the Black Death, Slavin teamed up with Johannes Krause, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. They were able to locate the remains from the Kara-Djigach and Burana cemeteries, which had been excavated and moved to Russia in the late 19th century.

Together with archaeogeneticist Maria Spyrou at the University of Tübingen, Germany, they sequenced the ancient DNA from seven people whose remains they had recovered and found Y. pestis DNA in three of the specimens from the Kara-Djigach cemetery.

Upon further analysis of the full genomes, they discovered that the bacteria were the direct ancestors of the strains associated with the Black Death. Moreover, the same bacteria was also the origin of the great majority of Y. pestis variants that exist today.

It was a signal of rapid diversification of the Y. pestis just before the Black Death, according to Krause.

This study of ancient DNA from Kyrgyz graves along with samplings of modern strains from marmots and other rodents in Kyrgyzstan, Kazakhstan, and Xinjiang in northwest China that surround the Tian Shan mountain range — showing the closest link between the two Y. pestis strains — point to Central Eurasia as the origin of the Black Death. “We can’t really say it’s that village or that valley, but it’s likely that region,” said Krause.

Slavin added that Tian Shan mountain range as the epicenter for the Black Death was most probable of all places since it was part of the ancient Silk Road. The graves in Kyrgyzstan contained goods from various regions, like foreign currency and corals from the Mediterranean and pearls from the Indian Ocean. “We can hypothesize that trade, both long distance and regional, must have played an important role in spreading the pathogen westward.”

Indeed, in October 1347, the Black Death reached the shores of Europe upon the arrival of a dozen ships from the Black Sea at the port of Messina in Sicily. It quickly spread to France, Italy, England, and the rest of Europe, along with North Africa.

Today, the Plague is endemic to the Democratic Republic of Congo, Peru, and Madagascar.