Seven viral variants found in the United States with the same mutation

When Americans are worried about the first identified variant England And South Africa Spreading across the United States, scientists are discovering many new variants that began here. Even more worrisome, many of these variants appear to be evolving in the same direction, potentially threatening their own infectivity.

so Survey A research team posted on Sunday reported seven growth lines of the new coronavirus found in states across the country. All of them have evolved mutations in the same genetic character.

Jeremy Kamil, a virologist at the Center for Health Sciences, Louisiana State University, Shreveport, said: And co-author of a new study.

It is unclear whether it makes the mutant more contagious. However, scientists are very suspicious because mutations appear in genes that affect the way the virus enters human cells.

“I think there are clear signs of evolutionary benefits,” said Dr. Kamil.

The history of life is full of examples of so-called convergent evolution, in which different strains follow the same path. Birds acquired wings as they evolved from feathered dinosaurs. For example, just as bats evolved from mammals such as fur-covered shrews. In both cases, natural selection created a pair of flat surfaces that could be flapped to generate lift. Bats and birds can fly into the sky as well, filling ecological niches that other animals couldn’t.

Charles Darwin was the first to recognize convergent evolution by studying living animals.In recent years, virologists have discovered it Viruses can evolve convergently,Also. For example, HIV occurred when several species of virus were transferred from monkeys and apes to humans. Many of those HIV strains have acquired the same mutations that have adapted to our species.

As the coronavirus diverges into new variants, researchers are observing Darwin’s theory of evolution daily.

Dr. Kamil came across several new variants while sequencing samples from a coronavirus test in Louisiana. At the end of January, he observed an unfamiliar mutation in many samples.

The mutation changed the surface-studded protein of the coronavirus. Known as a spike protein, it is a folded chain of over 1,200 molecular building blocks called amino acids. Dr. Kamil’s viruses all shared a mutation that modifies amino acid position 677.

Upon investigating these mutant viruses, Dr. Kamil found that they all belonged to the same strain. The first virus in the lineage dates back to December 1. In the next few weeks it became more common.

On the night of his discovery, Dr. Kamil uploaded the viral genome to an online database used by scientists around the world. The next morning he received an email from Daryl Domman at the University of New Mexico. He and his colleagues have just found the same variant in their state with the same 677 mutations. Their sample dates back to October.

Scientists wondered if the strain they found was the only one with the 677 mutation. Upon scrutinizing the database, Dr. Kamil and his colleagues found six other strains that independently acquired the same mutation.

Since the United States has sequenced the genome from less than 1% of coronavirus test samples, it is difficult to answer even the basic questions about the prevalence of these seven strains. Researchers have found samples from strains scattered throughout the country. But they don’t know where the mutation first happened.

Emma Hodcroft, an epidemiologist at the University of Bern and co-author of the new study, said: “At this time, I am very hesitant to locate the origin of any of these strains.

It is also difficult to say whether the increase in variants is actually the result of them being more contagious. For all the holiday season trips, they may have become more common. Or it could have exploded during a superspreader event at a bar or factory.

Still, scientists are worried because mutations can affect the ease with which the virus can enter human cells.

Infection begins when the coronavirus uses the tip of a peplomer to latch onto the surface of human cells. It then releases the harpoon-like arm from the base of the spike, attracting itself to the cell and delivering the gene.

However, before the virus can carry out this invasion, the peplomer must hit the human protein on the surface of the cell. After that contact, the spike twists freely, exposing the tip of the harpoon.

The 677 mutation is thought to alter the spike protein next to where the protein nicks the virus, making it easier for the spike to be activated.

Jason McLellan, a structural biologist at the University of Texas at Austin who was not involved in the study, called it “significant progress.” However, he warned that the way the coronavirus unleashes its harpoon is still quite mysterious.

“It’s hard to know what these alternatives are doing,” he said. “In practice, we need to follow up with some additional data.”

Dr. Kamil and his colleagues are starting their experiments to see if mutations actually make a difference in infections. If the experiment confirms their suspicion, the 677 mutation will join a small and dangerous club.

Convergent evolution has also changed some other spots of peplomer. 501st amino acid For example, it is mutated in many strains, including the first infectious subspecies observed in the United Kingdom and South Africa. Experiments have shown that 501 mutations alter the tip of the spike. With this change, the virus is firmly anchored in the cells and infects more effectively.

Scientists predict that the coronavirus will converge to more mutations that will benefit not only other viruses but also our own immune system. However, evolutionary biologist at the University of Pittsburgh and co-author of the new study, Vaughn Cooper, said laboratory experiments alone could not reveal the extent of the threat.

To really understand what the mutation is doing, he said scientists would need to analyze a much larger sampling of coronaviruses collected from all over the country.But for now, they can only see a relatively small number of genomes collected by State and university lab patchwork..

“It’s ridiculous that our country hasn’t come up with a national strategy for surveillance,” Dr. Cooper said.