Science

The earliest strain of plague dating back to a 5,000-year-old hunter-gatherer

Yersinia pestis Is the most famous bacterium for its role in bubonic plague, which devastated Europe, Asia and North Africa in the 1300s, and is known as black death, which killed half of Europe’s population. Through genetic analysis of the teeth and bones of a 5,000-year-old hunter-gatherer, researchers discovered the earliest known strain of the bacterium that causes this plague.

This oldest known strain Y.pestis It was discovered in a man between the ages of 20 and 30 whose skeleton was excavated from what is now Latvia in the late 1800s, known as “RV2039”. Scientists sequence the male genome through tooth and bone samples, test it for bacterial and viral pathogens, and Y. pestis.

RV2039 jawbone

Dominik Göldner, BGAEU, Berlin

Through subsequent reconstruction of the bacterial genome and comparison with other ancient strains, scientists have concluded that this is actually the oldest strain. Y.pestis Discovered so far. Team research revealed that this early strain only lacked several genes from the same bacterium behind bubonic plague, one of which was the key to subsequent success. was.

“Very surprising is that this early strain already has a more or less complete gene set. Yersinia pestis, And only a few genes are missing, “says senior author Ben Klaus Kyora. “But even the slightest change in genetic setting can have a dramatic impact on pathogenicity.”

Scientists have discovered that ancient strains lack genes that allow fleas to act as vectors and spread plague to human hosts. They believe that it took more than 1,000 years for the bacteria to make all the mutations needed for this flea-based infection, so the disease experienced by RV2039 was much milder than the medieval version. I conclude.

Y.pestis The presence in his bloodstream indicates that he probably died of a bacterial infection, but the course of the illness was probably slow. Scientists suspected that the people buried with them were not infected with plaque and were bitten by an infected rodent and became ill, so it is unlikely to be contagious. is showing.

“Isolated cases of animal-to-human transmission can explain the different social environments in which these ancient sick humans were discovered,” says Klaus-Kyora. “We see it in grassland nomads, fishing hunter-gatherers, and farmers’ communities – a completely different social environment, but always spontaneous. Yersinia pestis Case. “

Current Latvian site where RV2039 was discovered
Current Latvian site where RV2039 was discovered

Harald Lübke, ZBSA, Schloss Gottorf

This finding may reshape our understanding of how infectious diseases have become established in large cities in Europe and Asia, and the low contagiousness of this early strain is historical. It suggests that it may not have played a significant role in population decline. Moreover, understanding its history can also inform our understanding of the history of the human genome.

“Various pathogens and the human genome have always evolved together,” says Krause-Kyora. “We know Yersinia pestis Perhaps it killed half of Europe’s population in a short period of time, so it should have a significant impact on the human genome. However, even before that, there may have been a major turnover in immune genes at the end of the Neolithic era, at which point there may have been significant changes in the pathogen status. “

The study was published in the journal Cell report..

Source: Via Cell Press Eurek Alert



https://newatlas.com/science/earliest-strain-plague-5000-year-old/ The earliest strain of plague dating back to a 5,000-year-old hunter-gatherer

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