After 800 years… DNA analysis resolves the controversy over the origin of the Black Death plague | Sciences

To understand pandemics, it is necessary to understand the overall picture of the evolution of a bacterium or virus, to know the different stages of evolution, to avoid treating different strains as isolated phenomena and to view the epidemic in an ecological and social to put context.

It is no exaggeration to say that explaining the date of origin of the Black Death – the deadliest epidemic ever in humans – was until recently the most mysterious medical mystery in human history.

The Black Death, which lasted from 1346 to 1353 AD, was the first wave of a long-term pandemic that lasted from the 14th to the 19th century and killed between 50 and 60% of the population in Europe, the Middle East and killed North Africa. , and an unknown number of the population In Central Asia.

many imaginations

Many researchers and scientists have put forward many interpretations, perceptions and theories over the centuries, and researcher Philip Slavin, professor of history at the University of Stirling in Scotland, mentioned some of them in his article published on The Conversation website. Among these perceptions, scholars who saw the plague in Europe and the Islamic world said that the Black Death plague originated in the East, specifically in the regions where Central Asia, Mongolia and China intersect.

The French scientist Joseph de Jane also put forward an academic theory in 1758 indicating that the plague originated in China, and epidemiologists mentioned that Central Asia in general and the Tian Shan region (a mountainous region on the border between China and Kyrgyzstan) is the cradle. of the Black Death plague.

Tombstones Inscribed Cause of Death Key To Solving Mystery That Confused Scientists For 8 Centuries (Websites)

Some scholars have mentioned that the source of the plague was other regions such as northern Iraq, the Caucasus, the Volga region in Russia, the western Ural Mountains, western Siberia, the Gobi Desert, and India. In fact, one of the historians mentioned that the beginning of the Black Plague is linked to a meteorite that hit the Earth in that period.

In a study published in 2013, a team of microbial scientists identified a major evolutionary mutation in which the main strain of the pandemic (Faction Zero) mutated and split into 4 new strains, namely families 1 to 4. The researchers this mutation metaphorically called the “Big Bang.” The strain (or family 1) is the one associated with the Black Death plague.

The study, based on computer probabilities, dates this mutation to the period between 1142 and 1339. The researchers concluded that the plague bacteria may have originated in the Qinghai (Tibet) Plateau in Asia. Based on this study, researchers believed that the pandemic spread widely in the 13th century due to the expansion of the emerging Mughal Empire.

strange graves

The turning point in the search for the origin of the Black Plague was when Philip Slavin found records describing the “Kara-Gigach” tombs, discovered by the Russian archaeologist Nikolai Bantusov in 1885 and 1886 and analyzed by the Russian scientist Daniel Choulson.

**Inland** Map showing the location of cemeteries
Map showing the location of the Kara Zegach Tombs and the Tian Shan Mountains region (websites)

Out of a total of 467 graves covering the period 1248-1345, there are 118 graves dating back to the year 1338, which is a suspiciously large number of deaths. The headstones did not contain much detail about the graves being remembered, except for the names and dates of death, but 10 of them had words explaining the cause of death, and one of these messages on the headstones said: Here lies the faithful Sanmaq . He died of the plague.”

This greatly roused the curiosity and astonishment of Philip Slavin; Not only did it refer to the “epidemic”, but everyone believed that it dated back to the years 1338 and 1339, that is, about 7 or 8 years before the arrival of the Black Plague epidemic in the Crimea and its subsequent spread in Europe and North Africa. Philip assumed with a strong feeling that this connection was not coincidental and that it needed extensive scientific study.

Philip Slavin joined a multidisciplinary team of 13 researchers and scientists to unravel this mystery. Scientists examined the genetic code of DNA extracted from the remains of Black Death victims whose graves share the same date, 1338 and 1339; And they got conclusive results from the teeth of 7 of them. The team published the results of the study in the journal “Nature” on June 15.

Unprecedented important discoveries

Genetic analysis revealed the presence of plague bacteria in 3 samples, confirming that it is the cause of the plague. The scientists noted that the strain (in the null family) seemed to predate the genetic mutation, from which the Black Death strain emerged shortly after; Therefore, the study indicated that the Black Plague began shortly after (or perhaps during) the outbreak of this pandemic between 1338 and 1339.

The common rodents in Tian Shan that transmitted the plague bacteria are badgers (Shutterstock)

Of course, there is no indication that the Karajigac cemetery was the exact source of the plague, but scholars believe that the disaster began somewhere in the vast Tian Shan, most likely not far from this site.

It is worth noting that the plague bacteria (Y. pestis) lives among wild rodents, and the common perception was that mice were the source of the plague, but the common rodents in the Tian Shan area that transmitted the plague bacteria are badgers, and therefore their colonies are probably the first source of the plague outbreak between 1338 and 1339.

The other important discovery is that the ancient plague strains found today in badger colonies in the Tian Shan plague reservoirs are much earlier in evolution and even older than the bacteria found in the “Kara Jigach” cemetery.

This is why scientists are sure that the bacteria discovered in the victims of the Kara Zegach cemetery evolved internally in the colonies of local badgers in the vast Tian Shan region, and did not move there from another distant habitat not. At some point later, the bacteria then spread to the human population of the area.

The common perception was that mice were the source of the plague (Shutterstock)

The importance of this study

This study resolved the age-old controversy over the origin and location of the Black Plague, considered the deadliest epidemic in humans. Otherwise, this study has provided a model that scientists and researchers can benefit from in the emergence of epidemics and other pandemics.

To understand the new pandemics – and the Corona pandemic is far from us – it is necessary to understand the full picture of the evolution of bacteria or viruses, to know the different stages of development, and to prevent that different strains are treated as isolated phenomena of each. others Placing the epidemic in the environmental and social contexts is necessary to understand how these diseases develop and spread.

The study also provides a model that embodies the need for fruitful collaboration between colleagues and researchers from various fields, specializations, skills, approaches and experiences, and that this combination of skills and experiences is the future of historical research based on genetic code analysis and genetic engineering.

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