Team identifies story of SARS-CoV-2 origin

Researchers say that the pedigree that produced SARS-CoV-2, the virus responsible for the COVID-19 pandemic, has been circulating in bats for decades.

They also warn that they are likely to contain other viruses that have the ability to infect humans.

The discoveries made by the researchers by reconstructing the evolutionary history of SARS-CoV-2 impact the prevention of future pandemics caused by this lineage.

“Coronaviruses have highly genetically engineered genetic material, which means that different regions of the viral genome can be derived from multiple sources,” said Maciej Boni, associate professor of biology at Penstate. States.

“This made it difficult to reconstruct the origin of SARS-CoV-2. We need to identify all regions that are being recombined and track their history.”

SARS-CoV-2 “Family tree”

The team used three different bioinformatics approaches to identify and delete recombination regions within the SARS-CoV-2 genome. Next, we reconstructed the phylogenetic history of the non-recombinant region and compared them to each other to identify the specific viruses that have previously been involved in the recombination event.

They were able to reconstruct the evolutionary relationship between SARS-CoV-2 and its closest known bat and pangolin virus.

Researchers have discovered that the strain of the virus to which SARS-CoV-2 belongs diverged from other bat viruses about 40 to 70 years ago. Importantly, SARS-CoV-2 is genetically similar to RaTG13 coronavirus (approximately 96%). Rhinolophus affinis A team of horseshoe bats that broke out in Yunnan, China in 2013, discovered in 1969 that they had diverged from RaTG13 a relatively long time ago.

Philip Lemay, Principal Investigator in the Department of Evolutionary and Computational Virology at KE, said: Leuven.

The team discovered that one of the old properties that SARS-CoV-2 shares with its relatives is the receptor binding domain (RBD) on the spike protein. This allows the virus to recognize and bind to receptors on the surface of human cells. ..

“This means that other viruses that can infect humans are prevalent in the Chinese bat bat,” David L. Robertson, professor of computational virology at the Glasgow University Center for Virus Research. Says.

The leap from bats to humans

These viruses are Bat Are humans, or intermediate species, needed to make the leap? According to Robertson, for SARS-CoV-2, other research groups erroneously proposed that a major evolutionary change had occurred in Pangolin.

“SARS-CoV-2 RBD sequences have so far been found only in some pangolin viruses,” says Robertson. “In addition, another important function that might be useful in the ability of SARS-CoV-2 to infect humans (insertion of polybasic cleavage sites into spike proteins) is another important function associated with the SARS-CoV-2 virus. Not yet seen in bats.

“However, while it is possible that Pangolin could function as an intermediate host that promotes the transmission of SARS-CoV-2 to humans, evidence suggests that Pangolin infection is a requirement for bat virus to enter humans. No. Instead, our research suggests that SARS-CoV-2 may have evolved its ability to replicate in the upper respiratory tract of both humans and pangolins.

Will you strengthen monitoring next time?

The team concludes that better sampling is needed to prevent future pandemics Wild bats Implementation of a human disease surveillance system that can identify new human pathogens and respond in real time.

“The key to successful surveillance is knowing which viruses to look for and prioritizing those that are more likely to infect humans. We should have prepared for a second SARS virus.”

Boni added: “It was too late to respond to the first SARS-CoV-2 outbreak, but this is not the last. Coronavirus pandemic.. To catch the virus in this way, a more comprehensive and real-time surveillance system must be put in place, even if the case number is two digits. “

Additional co-authors are from Xi’an Jiaotong University of Liverpool. University of Hong Kong; University of Texas at Arlington; and University of Edinburgh.

Support for this research came from the European Research Council, the Medical Research Council, the Research Foundation-Flanders, China National Natural Science Foundation.

Source: Pennsylvania