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On the origin and continuing evolution of SARS-CoV-2
Xiaolu Tang1, Changcheng Wu1, Xiang Li2
1State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China.
National Science Review
|October 22, 2021
Summary
Molecular analysis reveals significant divergence between SARS-CoV-2 and bat coronaviruses, with natural selection driving variations in the spike protein. Two main SARS-CoV-2 lineages, L and S, were identified, with L being more prevalent.
Area of Science:
- Virology
- Genomics
- Evolutionary Biology
Background:
- The emergence of SARS-CoV-2 has led to a global health crisis.
- Understanding the evolutionary origins and genetic diversity of SARS-CoV-2 is crucial.
Purpose of the Study:
- To investigate molecular divergence between SARS-CoV-2 and related coronaviruses.
- To identify evolutionary mechanisms shaping SARS-CoV-2.
- To analyze the population genetics and lineages of SARS-CoV-2.
Main Methods:
- Comparative genomic analysis of SARS-CoV-2 and bat SARS-related coronaviruses (SARSr-CoV).
- Analysis of nucleotide variability and neutral site differences.
- Examination of the receptor-binding domain (RBD) of the spike protein.
- Population genetic analysis of 103 SARS-CoV-2 genomes using single nucleotide polymorphisms (SNPs).
Main Results:
- A 17% difference at neutral sites between SARS-CoV-2 and bat SARSr-CoV (RaTG13) indicates greater divergence than previously estimated.
- Natural selection, alongside recombination, likely drives variations in the spike protein's RBD.
- Two major SARS-CoV-2 lineages, L and S, were identified, defined by distinct SNPs.
- The L lineage was found to be more prevalent in the studied patient samples.
Conclusions:
- SARS-CoV-2 exhibits significant molecular divergence from related coronaviruses.
- Evolutionary pressures, including natural selection, are shaping viral variation.
- Further integrated genomic and epidemiological studies are urgently needed to understand the implications of these findings for COVID-19.
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