‘Ancient RNA virus epidemics occurred frequently during human evolution’

New research reveals clues to an epidemic that occurred over 25,000 years ago. TEK IMAGE/SCIENCEPHOTO LIBRARY/Getty Images
  • Genome adaptations could provide insight into a viral outbreak as far back as 25.000 years ago.
  • Several lines of evidence point to a coronavirus or similar virus that emerged among the ancestors of East Asian people.
  • The potential for evolutionary genomic methods to combat future pandemics by identifying old viral activity could be revealed by identifying ancient viral activity.

Researchers at the University of Arizona in Tucson, South Australia, and the University of Adelaide, South Australia, co-led a team of scientists who looked into human genomes in order to discover a link between ancient coronavirus outbreaks and past adaptation in modern people.

They hope that understanding the effect of past pandemics on genetic mutations will give scientists more “ammunition” in the arms raceTrusted Source against SARS-CoV-2 variants.

Yassine Souilmi, Ph.D., the lead author of the paper, is a postdoctoral research associate at the Australian Centre for Ancient DNA. His findings were published in the June 2021 issue of Current Biology.

The authors explain in their article

“Here we apply evolutionary analysis to human genomic data to recover selection events that involve tens of human gene interactions with coronaviruses including SARS-CoV-2 that probably started more than 20000 years ago.”

VIPs & RNA viruses

Positive natural selection has been a key factor in human history. It often targets virus-interacting proteins (VIPs). VIPs can either help build immunity or be hijacked by viruses.

This natural selection has persisted over the past 50,000 years, especially around VIPs that react to RNA viruses, such as coronaviruses.

Investigating VIP adaptations

Souilmi’s team culled genetic data from the 1000 Genomes Project, a vast catalog of human genetic variations.

Two statistical analyses detected genetic signals known as selective sweeps.

Researchers looked at selective sweep modifications in more than 400 VIPs who interact with coronaviruses. Data were collected from 26 different populations.

Relying on evidence that VIPs are what viruses harness to take over host cells, they focused on these genes. This approach was also taken because VIPs have a greater functional impact on viruses than other proteins.

Sweep signals more that 900 generations

Scientists discovered an antiviral pattern in sweep signals at 42 CoV/VIPs from five East Asian populations. This enrichment was not seen in any other populations.

These mutations could have increased in frequency over time, up to 200 generations or 5,000 years ago.

Also, the CoV-VIP proteins demonstrate antiviral and proviral effects and variations that affect SARS-CoV-2 susceptibility and COVID-19 severity in the current British population.

The paper points out that adaptations made in certain populations of humans do not necessarily mean that they are more vulnerable to viral diseases.

Medical News Today asked Martin Bachmann, Ph.D., an immunologist and professor of vaccinology at the University of Oxford’s Jenner Institute in the United Kingdom and the University of Bern in Switzerland, for his perspective on this research:

“It is amazing that you can analyse epidemics from 20,000 year ago without actually looking at any sample older than a few months. This shows how much information is hidden in the genomes of individuals and the entire population.

Harnessing evolutionary data to combat COVID-19

Souilmi, along with his colleagues, anticipate that their discoveries will aid in the development of drugs and therapies.

Currently, 11 drugsTrusted Source in use or in clinical trials target four of the 42 CoV-VIP genes that the team analyzed.

MNT also spoke with William Schaffner, M.D., professor of infectious diseases at Vanderbilt University in Nashville, TN.

Schaffner hopes this research will also lead to medical interventions, “so we can weather the epidemic and begin to manage it in a safer way than letting nature have its way.”

Professor Xu noted that East Asians would have to face a high death rate in order to obtain genetic protection against the ancient disease. The cost of developing natural immunity is a steeper price than the modern world could avoid with scientific breakthroughs.

Study’s limitations

Souilmi along with his co-authors warn that some of the datasets they used in their evaluations were derived from modern populations that have different ancestries to the East Asian subsets that contained the CoV-VIP gene.

Although ancient DNA samples may have supported the existence of CoVVIP mutations in the past, they are still not known.

The researchers also note that their population genomics approach could not pinpoint the causal variants for the CoV-VIP proteins that they examined in the East Asian ancestors.

They speculate that another virus with similar VIPs to coronaviruses could have caused the adaptations they observed.

It’s worth noting, however, that one of the study authors is a consultant at Interline Therapeutics or Maze Therapeutics. He has also received stock from them. They also hold shares in Tenaya Therapeutics. They have no competing interests.

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