SARS-CoV-2 Evolution
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COVID-19 virus

In order to understand how the virus behind COVID-nineteen mutates and continues to pose a threat to us, scientists are studying its origin and what made it so good at infecting humans. Recent work suggests the virus, SARS-Co-V-two began in bats and jumped to humans. That's because the closest relative to the virus has been found in Horseshoe bats and Pangolins.

Scientists examined the genomes of one hundred thirty thousand SARS-CoV-two viruses isolated early in the pandemic and compared them to sixty-nine viruses in bats for genetic signs of adaptation. They learned the pandemic viruses are from a subset of coronaviruses called the sarbecoviruses. These are "generalists" meaning they've evolved to easily infect mammals which explains why SAR-CoV-two easily transmitted to humans.

With RNA as its genetic information, it mutates nearly each time it replicates, fortunately at a slower rate than influenza, for example. The mutations that take hold is determined by people's immune responses, vaccines, and the use of antivirals. We know the virus began changing in late two thousand twenty when variants such the Beta and Alpha strains emerged.

The vaccines are good at limiting its chances to adapt, but they also apply pressure for the virus to evolve resistance to them. We have to keep monitoring the virus for new variants and design booster vaccines to stay ahead of this disease.

For more information…

Natural selection in the evolution of SARS-CoV-2 in bats created a generalist virus and highly capable human pathogen
Virus host shifts are generally associated with novel adaptations to exploit the cells of the new host species optimally. Surprisingly, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has apparently required little to no significant adaptation to humans since the start of the Coronavirus Disease 2019 (COVID-19) pandemic and to October 2020...

Evolutionary origins of the SARS-CoV-2 sarbecovirus lineage responsible for the COVID-19 pandemic
There are outstanding evolutionary questions on the recent emergence of human coronavirus SARS-CoV-2 including the role of reservoir species, the role of recombination and its time of divergence from animal viruses. We find that the sarbecoviruses-the viral subgenus containing SARS-CoV and SARS-CoV-2-undergo frequent recombination and exhibit spatially structured genetic diversity on a regional scale in China...

On the origin and continuing evolution of SARS-CoV-2
The SARS-CoV-2 epidemic started in late December 2019 in Wuhan, China, and has since impacted a large portion of China and raised major global concern. Herein, we investigated the extent of molecular divergence between SARS-CoV-2 and other related coronaviruses...

CDC SARS Response Timeline