Objective In December 2019 a novel coronavirus (SARS-CoV-2) that is causing the current COVID-19 pandemic was identified in Wuhan, China. Many questions have been raised about its origin and adaptation to humans. In the present work we performed a genetic analysis of the Spike glycoprotein (S) of SARS-CoV-2 and other related coronaviruses (CoVs) isolated from different hosts in order to trace the evolutionary history of this protein and the adaptation of SARS-CoV-2 to humans. Results Based on the sequence analysis of the S gene, we suggest that the origin of SARS-CoV-2 is the result of recombination events between bat and pangolin CoVs. The hybrid SARS-CoV-2 ancestor jumped to humans and has been maintained by natural selection. Although the S protein of RaTG13 bat CoV has a high nucleotide identity with the S protein of SARS-CoV-2, the phylogenetic tree and the haplotype network suggest a non-direct parental relationship between these CoVs. Moreover, it is likely that the basic function of the receptor-binding domain (RBD) of S protein was acquired by the SARS-CoV-2 from the MP789 pangolin CoV by recombination and it has been highly conserved.
【저자키워드】 SARS-CoV-2, spike glycoprotein, molecular evolution, Recombination, natural selection, genealogy, 【초록키워드】 coronavirus, S protein, COVID-19 pandemic, Human, Novel coronavirus, Protein, RBD, humans, Sequence analysis, RaTG13, CoV, glycoprotein, Haplotype, nucleotide, S gene, Phylogenetic tree, identity, CoVs, genetic analysis, recombination event, pangolin CoV, Host, objective, Wuhan, China, Result, performed, conserved, raised, question, the receptor-binding domain, the S protein, parental, the Spike, pangolin CoVs, the SARS-CoV-2, 【제목키워드】 Receptor binding domain, SARS-CoV-2 spike protein, RaTG13, bat-CoV, pangolin-CoV,