An ancient strain of the corona virus may have infected the ancestors of people living in present-day East Asia as early as 25,000 years ago and millennia after, according to a recent study.
Ancient corona virus illustration, 25,000 years ago. The current COVID-19 pandemic has claimed the lives of more than 3 million people and shows how vulnerable people are to the genetically modified corona virus. However, this threat seems to have occurred since the early days when humans had to fight these dangerous viruses. “There are always viruses that infect humans,” said senior study author David Enard, associate professor of ecology and evolution at the University of Arizona, USA. Viruses are actually one of the main drivers of natural selection in the human genome. That’s because genes that increase the chances of the pathogen’s survival are more likely to be passed on to new generations. ” Using modern tools, researchers can detect traces of these ancient pathogens by precisely identifying how they promote natural selection in today’s human DNA. Accordingly, this information can provide valuable insight to help predict future pandemics. Enard said: “Almost always is when things that happened in the past are more likely to happen in the future.” Using information available in public databases, Enard and his team analyzed the genomes of 2,504 people across 26 different human populations around the world. When corona viruses get inside human cells, they attack the cell’s machinery to replicate. This means that the viral success depends on its interaction with hundreds of different human proteins. Researchers magnified a set of 420 human proteins known to interact with the corona virus, 332 of which interact with SARS-CoV-2, the virus that causes COVID-19. Most of these proteins help viruses multiply inside cells, but some help cells fight viruses. The genes that encode those proteins mutate continuously and randomly, but if the mutation gives the gene an advantage, such as a better resistance to the virus – then the gene has a chance to be passed on. next or selected higher. Indeed, the researchers found that, in people of East Asian descent, certain genes interacting with the corona virus were selected. In other words, over time certain variations show up more often than expected. This set of mutations may have helped the ancestors of the human population in this region become more ancient antiviral by altering the amount of protein produced by the cell. The genetic variations encoding 42 of the 420 proteins they analyzed began to increase in frequency about 25,000 years ago, the researchers found. The spread of beneficial variants continued until about 5,000 years ago. This suggests that the ancient virus continued to threaten these populations for a long time. Viruses cause pressure to adapt “Viruses exert some of the strongest selective pressures on humans to adapt, and corona viruses have probably been around since,” said Joel Wertheim, associate professor at the Faculty of Medicine at the University of California, San Diego. long before man existed. However, it is difficult to say whether the virus that caused this evolution is the corona virus, but it seems to be a plausible theory. David Enard agrees that the ancient pathogen that harmed our ancestors may not have been the corona virus; instead, it is possible that another virus that has happened to interact with human cells in the same way that corona viruses do. Another group of researchers recently discovered that sarbecovirus, a family of the corona virus that includes SARS-CoV-2, first evolved 23,500 years ago, at the same time as variations in the genes that encode the proteins related to the corona virus have appeared for the first time in humans. Findings of the sarbecovirus virus were also published in bioRxiv on February 9 and have yet to be peer reviewed. While these findings are compelling, they do not change our understanding of which populations are more likely to survive SARS-CoV-2 infection. Although, there is no evidence that adaptation of this ancient gene protects modern humans from SARS-CoV-2. Enard and his team now hope to work with virologists to understand how this adaptation helped ancient humans survive exposure to this protozoan strain of the corona virus. The team also hopes that such ancient genomic studies could eventually be used as an “early warning system” for future pandemics. David Enard adds, although we clearly see the impact of this ancient virus on human ancestors, future generations will not be able to see traces of SARS-CoV-2 in the genome. our. Thanks to vaccination, there is no time for the virus to promote evolutionary adaptation.
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