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Updated: Jul 19, 2025
12:23
In Vitro Selection of Aptamers to Differentiate Infectious from Non-Infectious Viruses
Published on: September 7, 2022
1.7K
Contributions of adaptation and purifying selection to SARS-CoV-2 evolution
1Biozentrum, University of Basel, Spitalstrasse 41, Basel 4053, Switzerland.
Virus Evolution
|August 18, 2023
Summary
SARS-CoV-2 evolution shows distinct rates for genetic changes. While synonymous mutation rates are stable, non-synonymous rates accelerated overall, indicating adaptive evolution drove variant emergence.
Area of Science:
- Virology
- Evolutionary Biology
- Genomics
Background:
- SARS-CoV-2 evolution has produced more transmissible and immune-evasive variants.
- These variants significantly impacted the COVID-19 pandemic's trajectory.
Purpose of the Study:
- To analyze SARS-CoV-2 evolution over 2.5 years.
- To estimate synonymous and non-synonymous mutation rates within clades and overall.
- To investigate the drivers of variant evolution.
Main Methods:
- Analysis of viral evolution data spanning 2.5 years.
- Separate estimation of synonymous and non-synonymous evolutionary rates.
- Quantification of mutation spectrum and purifying selection across viral proteins.
Main Results:
- Synonymous mutation rates are consistent at approximately 6-7 changes per year.
- Non-synonymous rates decreased in 2021-2022 but the overall rate across variants accelerated to ~26 changes per year.
- Massive global sampling enabled site-specific fitness cost estimation.
Conclusions:
- The accelerated overall non-synonymous evolution suggests adaptive processes distinct from typical transmission chains.
- Accessory proteins show limited evolutionary constraints, while many other proteins experience strong purifying selection.
- Global viral sampling is sufficient for detailed evolutionary analysis.
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