Omicron Has Terrible Mutations. They may not work well together.


The Omicron variant of the coronavirus has alarmed many scientists because of the large number of genetic mutations it carries – about 50 in total, including at least 26 unique to it. more doesn’t necessarily mean worse: Mutations sometimes work together to make a virus more terrifying, but they can also destroy each other.

“In principle, mutations can also work against each other,” said evolutionary biologist Jesse Bloom of the Fred Hutchinson Cancer Research Center in Seattle. “However, in this case evolutionary selection is more likely to lead to the spread of a new variant that is more favorable than combinations of unfavorable mutations.”

Still, this phenomenon, called epistasis, is why scientists are reluctant to speculate about Omicron’s properties, even though individual mutations in the variant are associated with greater transmissibility or the ability to circumvent the body’s immune defenses.

“It’s important to get a sense of the full meaning of the virus,” said Penny Moore, a virologist with the National Institute of Infectious Diseases in South Africa.

Dr. Moore’s team is one of dozens worldwide trying to figure out if available vaccines work against Omicron. Rather than making decisions based on a subset of mutations, researchers create artificial versions of the virus that contain all of the Omicron mutations.

That’s a lesson researchers learned when the Beta variant emerged in South Africa last year. They estimated the variant’s ability to evade immunity based on a particular mutation, E484K. But Beta also had two other mutations that appeared to affect susceptibility to vaccines.

Dr. “The combination of these three mutations was more resistant than a virus containing only E484K,” Moore said. Examining the single mutation “turned out to be misleading.”

Omicron carries a mutation called N501Y, which is thought to allow the virus to bind more tightly to human cells. This mutation was also present in the Alpha variant and was linked to its infectivity.

Dr. “Still, it was Delta that didn’t have a specific mutation and was more contagious than Alpha,” Bloom said. “Because Delta has other mutations that increase transmissibility.”

The infectivity of a variant depends not only on how well the virus binds to receptors on human cells, but also on the stability of the virus, where it multiplies in the respiratory tract and how much is inhaled.

Omicron has a number of mutations, all linked to tighter binding to human cells. Dr. “But acting together can have a slightly different effect,” Bloom said. For this reason, he added that he could not predict how the variant would act in the body.

This will require ongoing laboratory work around the world.



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