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Tufts University School of Medicine

How Viruses Mutate and Create New Variants

“A virus will make hundreds to thousands of copies of itself every time it is in a cell,” says Marta Gaglia. “The chances of getting a mutant is high just because there’s so many replications happening.” Here, the Alpha variant virus. Photo: NIAID
Wednesday, June 9, 2021 - 8:00pm

As the COVID-19 pandemic continues, new variants of the SARS-CoV-2 virus pop up, and some lead to increasing infections. The main new variants—named Alpha, Beta, and Gamma and first identified in Britain, South Africa, and India, respectively—have properties that make them more successful in transmitting and replicating than the original virus.

recent report, for instance, shows that the Alpha variant, which is now the dominant variant in the United States, works by disabling the immune system’s first line of defense, interferon cells, which signal the body to attack viruses.

Viruses are not technically living things—they invade living cells and hijack their machinery to get energy and replicate, and find ways to infect other living organism and start the process over again.

How viruses mutate largely has to do with how they make copies of themselves and their genetic material, says Marta Gaglia, an associate professor of molecular biology and microbiology at the School of Medicine. Viruses can have genomes based on DNA or RNA—unlike human genomes, which are made up of DNA, which then can create RNA.

Gaglia studies how viruses take control of infected cells and reprogram the cells’ machinery to reproduce themselves. “We’ve been working on a protein that the virus encodes that destroys the host RNA, blocking the cells from being able to express their own protein and blocking, among other things, antiviral response,” she says.

Tufts Now talked with Gaglia to learn more about how different viruses mutate and what it might mean for the COVID-19 virus and vaccines’ ability to stop its transmission.

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