7 Virus Variants Found in U.S. Carrying the Same Mutation
As Americans eagerly looked at previously identified variants United Kingdom And South Africa Spanning the United States, scientists are finding many new variants that originated here. On the subject of more, many of these variants seem to develop in one direction – possibly becoming their own infectious threat.
in study Posted on Sunday, a team of researchers reported seven growing pedigrees of the novel coronavirus spotted in states across the country. They all have developed a mutation in the same genetic paper.
“There is clearly something going on with this mutation,” said Jeremy Kamil, a virologist at the Louisiana State University Health Sciences Center and co-author of the new study.
It is not clear whether this makes variants more contagious. But because the mutation appears in a gene that affects how the virus enters human cells, scientists are highly suspicious.
“I think there is a clear signature of an evolutionary advantage,” Dr. Kamil said.
The history of life is full of examples of so-called convergent evolution, in which different genealogies follow the same path. Birds gained wings as if they evolved from feathered dinosaurs, for example, as bats did when they evolved from furry, such as mammals. In both cases, natural selection gave rise to a pair of flat surfaces that could be flapped to lift – enabling bats and birds alike to take to the sky and fill an ecological niche that other animals could Could not do
Charles Darwin first recognized convergent evolution by studying living animals. In recent years, virologists have found that Viruses can grow convergent, Too. For example, HIV was produced when many species of viruses migrated from monkeys and apes to humans. Many of those lineages of HIV received the same mutation, as they were compatible with our species.
As coronaviruses now branch into new variants, researchers are looking at Darwin’s theory of the evolution of action, day in and day out.
Dr. Kamil made some new variances while filling samples with a coronovirus test in Louisiana. In late January, he noticed an unfamiliar mutation in several samples.
The mutation altered the protein that studs the surface of the coronovirus. Known as spike proteins, they are chains of more than 1,200 molecular building blocks called amino acids. Dr. Kamil’s virus shared all mutations that replaced the 677th amino acid.
Examining these mutant viruses, Dr. Kamil realized that they were all of the same lineage. The oldest virus in the lineage returned on 1 December. In later weeks, it became more common.
On the evening of his discovery, Drs. Kamil uploaded the virus’s genome to an online database used by scientists around the world. The next morning, he received an email from Darryl Dinwidi, a geneticist at the University of New Mexico. He and his colleagues had found only one variant in his state with only 677 mutations. Their specimens returned by October.
Scientists wondered if the lineage they discovered had only 677 mutations. Testing the database, Drs. Kamil and his colleagues found six other lineages that independently obtained the same mutation on their own.
Basic questions about the prevalence of these seven lineages are difficult to answer because the United States sequences less than 1 percent of the genome of coronovirus test samples. Researchers found scattered flaxseed in most parts of the country. But they cannot tell where the mutation first occurred.
“I am very hesitant at the moment to give a place of origin to any of these genealogies,” said Emma Hodcroft, an epidemiologist at the University of Bern and co-author of the new study.
It is also difficult to say whether the increase in variants is actually a result of their being more contagious. They may have become more common just because of travel in the holiday season. Or they may explode during superspreader events in bars or factories.
Nevertheless, scientists are concerned because mutations can abundantly affect how easily a virus reaches human cells.
An infection begins when a coronovirus uses the tip of a latch protein on the surface of a human cell. It then removes the harpoon-like arms from the base of the spike, which pulls up to the cell and transmits its genes.
Before the virus can carry out this attack, however, the spike protein has to collide with the human protein on the cell surface. After that contact, Spike breaks free to unleash his harpoon tips.
The 677 mutation replaces the spike protein next to the location where our proteins eject the virus, possibly making it easier for the spike to be activated.
Jason McLinnan, a structural biologist at the University of Texas at Austin, who was not involved in the study, called it “a significant advance”. But he cautioned that the way coronoviruses spread their harpoons is still quite mysterious.
“It’s hard to know what these replacements are doing,” he said. “This really needs to be followed up with some additional experimental data.”
Dr. Kamil and his co-workers are starting those experiments, hoping to see if the mutation actually makes the difference. If the experiments bear their suspicion, the 677 mutation will join a small, dangerous club.
Convergent evolution has also replaced some other locations on the spike protein. 501st amino acid For example, mutations have occurred in several types of lineages, including infectious variants first seen in the United States and South Africa. Experiments have shown that the 501 mutation alters the very tip of the spike. This change allows the virus to latch onto the cells more tightly, and infects them more effectively.
Scientists predict that coronavirus will converge on more mutations that will give them an advantage – not only against other viruses, but also our own immune system. But Watan Cooper, an evolutionary biologist at the University of Pittsburgh and co-author of the new study, said that laboratory experiments alone would not reveal the extent of the danger.
To understand what the mutations are doing, he said, scientists would need to analyze a much larger sample of coronavirus collected from across the country. But right now, they can only see a relatively small number of stored genes A patchwork of state and university laboratories.
“It is ridiculous that our country is not coming up with a national strategy to monitor,” Dr. Cooper said.