An ancient virus 20 thousand years ago left the same traces in the genetic material of the inhabitants of East Asia as Sars-CoV-2
Photo: GLOBAL LOOK PRESS
Over the past 20 years, three dangerous coronavirus epidemics have broken out in the world. Severe Acute Respiratory Syndrome (SARS or SARS in English) broke out in China in 2002. The disease was very difficult, every tenth case ended in death, but the spread of the virus was strangled in the bud. About 800 people became victims of SARS. Another member of the coronavirus family, MERS, or Middle East Respiratory Syndrome, made itself felt in 2012 in Saudi Arabia. It also turned out to be extremely aggressive, but in its ability to transmit to other people it was inferior to Sars-CoV-2: it infected about 2,500 people worldwide, 850 of them died. Sars-CoV-2 has already killed about 4 million people.
However, before that, there was another large-scale coronavirus epidemic in the history of mankind, traces of which were preserved in the genetic material of the population of East Asia.
An international team of scientists from universities in the United States and Australia conducted a genetic investigation using data from the 1000 Genomes Project. This is the most detailed catalog of human genetic variations to date, as part of the project, the genomes of 2,500 people have been fully read. In this particular study, genome sequences from 26 different populations were analyzed.
– The modern human genome contains information about evolution over tens of thousands of years. This can be compared to tree rings, the study of which gives us an idea of the conditions in which it grew, – explained one study author Kirill Alexandrov, professor at the Center for Tropical Cultures and Biomaterials at the Queensland University of Technology (Brisbane, Australia).
How ancient covid was calculated
Viruses have a huge impact on human evolution. And the targets of natural selection have often been proteins that physically interact with viruses – for example, are involved in immune defenses or are used by viruses to hijack host cells.
But how to calculate when the ancient epidemic happened by the “annual rings” in the genome? Over time, mutations are constantly accumulating in all genes, most of which are harmless, explains Professor Aleksandrov. The mutation rate can be figuratively represented as a constantly ticking genetic clock. But when there is pressure from natural selection – for example, a deadly epidemic has broken out – the clocks of some genes start ticking much faster as they accumulate beneficial mutations.
Scientists compared a large number of sequenced genomes and found that 20,000 years ago, the clocks of many of the genes that SARS-CoV-2 uses to manipulate human cells started ticking three times faster. Since this happened almost simultaneously – roughly 900 generations ago – this indicates a viral pandemic caused by a similar virus.
SARS-CoV-2 left his “fingers”
Next, scientists analyzed whether the proteins that our ancestors acquired after the pandemic 20 thousand years ago interact with SARS-CoV-2 proteins. And got a positive result. The circle has closed: in the genome, the “fingerprints” of COVID-19, which operated on the planet tens of thousands of years ago, were indeed fingerprinted.
According to scientists, the coronavirus epidemic in East Asia was large-scale, spanning several generations. During the epidemic, natural selection favored gene variants that protected against severe disease. These changes have become entrenched in the genome of people from those regions of East Asia that are now China, Japan, Mongolia, North Korea, South Korea and Taiwan.
Ancient killer viruses will be registered
The research carried out by Professor Aleksandrov and his colleagues has not only historical but also serious practical significance. The team plans to carry out genomic analysis of other large populations of people and use the fingers in our genetic code to calculate the viruses that caused deadly epidemics in the distant past. If SARS-CoV-2 returned from oblivion, then other killer viruses are likely to resurrect.
“The method we have developed allows us to compile a list of potentially dangerous viruses and then develop diagnostics, vaccines and drugs in case they return,” the study authors said.
Resuscitation specialist at COVID hospital: Every hundredth sick person will die, no matter how hard the doctors try
The well-known physician Sergei Tsarenko believes that it is our own fault that mutant viruses have gone wild. It was necessary to get vaccinated faster (details)