On the origin and continuing evolution of SARS-CoV-2
#MMPMID34676127
Tang X
; Wu C
; Li X
; Song Y
; Yao X
; Wu X
; Duan Y
; Zhang H
; Wang Y
; Qian Z
; Cui J
; Lu J
Natl Sci Rev
2020[Jun]; 7
(6
): 1012-1023
PMID34676127
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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. Although we found only 4% variability in genomic
nucleotides between SARS-CoV-2 and a bat SARS-related coronavirus (SARSr-CoV;
RaTG13), the difference at neutral sites was 17%, suggesting the divergence
between the two viruses is much larger than previously estimated. Our results
suggest that the development of new variations in functional sites in the
receptor-binding domain (RBD) of the spike seen in SARS-CoV-2 and viruses from
pangolin SARSr-CoVs are likely caused by natural selection besides recombination.
Population genetic analyses of 103 SARS-CoV-2 genomes indicated that these
viruses had two major lineages (designated L and S), that are well defined by two
different SNPs that show nearly complete linkage across the viral strains
sequenced to date. We found that L lineage was more prevalent than the S lineage
within the limited patient samples we examined. The implication of these
evolutionary changes on disease etiology remains unclear. These findings strongly
underscores the urgent need for further comprehensive studies that combine viral
genomic data, with epidemiological studies of coronavirus disease 2019
(COVID-19).
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