A coronavirus epidemic hit East Asia 20,000 years ago, new study shows
By Amy Sood and Zixu Wang, CNN
Over the past 20 years, people have faced a series of outbreaks caused by coronaviruses, including SARS, MERS, and Covid-19. But humans may have faced the disease millennia ago, new research suggests.
A team of researchers from Australia and the United States has found evidence of a coronavirus epidemic that broke out more than 20,000 years ago in East Asia, according to a study published in the Current Biology scientific journal on Thursday.
In the study, the researchers studied the genomes of more than 2,500 people from 26 different populations around the world. They pinpointed the earliest interaction of the human genome with coronaviruses, which left genetic imprints on the DNA of modern-day people in East Asia.
The genomes they studied contain evolutionary information about humans tracing back hundreds of thousands of years, said lead author Yassine Souilmi -- information we've only learned to decode in recent years.
Viruses work by making copies of themselves. However, they don't have their own tools to do the duplication. "So they actually depend on a host, and that's why they invade a host and then they hijack their machinery to create copies of themselves," Souilmi said.
That hijacking of human cells leaves a mark we can now observe -- offering concrete evidence our ancestors were once exposed to and adapted to coronaviruses.
In the genomes, researchers found these genetic signals related to a coronavirus in five different populations located in China, Japan and Vietnam. The epidemic could have spread further beyond these countries, Souilmi added, but data isn't available in other parts of the region, so there's no way of knowing.
From these populations, Souilmi said the researchers found an affected group developed a beneficial mutation which helped to protect them from the coronavirus. Those with the mutation had "an edge" in survival, he said -- meaning over time, the population was made up of more people with the mutation than without.
"Over a long period of time, and along the exposure, this leaves a very, very clear marking in the genomes of their descendants," Souilmi said. "And that's the signature we actually use to detect this ancient epidemic, and also the timing of this ancient epidemic."
The study said the coronavirus plague occurred separately among different regions and spread across East Asia as an epidemic.
However, scientists don't know how ancient people lived through the epidemic, partially because it wasn't clear whether it was something seasonal like a flu, or continuous -- like the Covid-19 pandemic -- that infects people and keeps spreading all the time.
VIDEO: AN INTERNATIONAL STUDY HAS DISCOVERED A CORONAVIRUS EPIDEMIC BROKE OUT IN THE EAST ASIA REGION MORE THAN 20,000 YEARS AGO, WITH TRACES OF THE OUTBREAK EVIDENT IN THE GENETIC MAKEUP... view more
CREDIT: QUT
Genome study reveals East Asian coronavirus epidemic 20,000 years ago
An international study has discovered a coronavirus epidemic broke out in the East Asia region more than 20,000 years ago, with traces of the outbreak evident in the genetic makeup of people from that area.
Professor Kirill Alexandrov from CSIRO-QUT Synthetic Biology Alliance and QUT's Centre for Genomics and Personalised Health, is part of a team of researchers from the University of Arizona, the University of California San Francisco, and the University of Adelaide who have published their findings in the journal Current Biology.
In the past 20 years, there have been three outbreaks of epidemic severe coronaviruses: SARS-CoV leading to Severe Acute Respiratory Syndrome, which originated in China in 2002 and killed more than 800 people; MERS-CoV leading to Middle East Respiratory Syndrome, which killed more than 850 people, and SARS-CoV-2 leading to COVID-19, which has killed 3.8 million people.
But this study of the evolution of the human genome has revealed another large coronavirus epidemic broke out thousands of years earlier.
"The modern human genome contains evolutionary information tracing back tens of thousands of years, like studying the rings of a tree gives us insight into the conditions it experienced as it grew," Professor Alexandrov said.
In the study, the researchers used data from the 1000 Genomes Project, which is the largest public catalogue of common human genetic variation, and looked at the changes in the human genes coding for SARS-CoV-2 interacting proteins.
They then synthetised both human and SARS-CoV-2 proteins, without using living cells, and showed that these interacted directly and specifically pointed to the conserved nature of the mechanism coronaviruses use for cell invasion.
"Computational scientists on the team applied evolutionary analysis to the human genomic dataset to discover evidence that the ancestors of East Asian people experienced an epidemic of a coronavirus-induced disease similar to COVID-19," Professor Alexandrov said.
East Asian people come from the area that is now China, Japan, Mongolia, North Korea, South Korea, and Taiwan.
"In the course of the epidemic, selection favoured variants of pathogenesis-related human genes with adaptive changes presumably leading to a less severe disease," Professor Alexandrov said.
"By developing greater insights into the ancient viral foes, we gain understanding of how genomes of different human populations adapted to the viruses that have been recently recognised as a significant driver of human evolution.
"Another important offshoot of this research is the ability to identify viruses that have caused epidemic in the distant past and may do so in the future.
"This, in principle, enables us to compile a list of potentially dangerous viruses and then develop diagnostics, vaccines and drugs for the event of their return."
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