ABSTRACT
A novel beta-coronavirus, SARS-CoV-2, emerged in late 2019 and rapidly spread throughout the world, causing the COVID-19 pandemic. However, the origin and direct viral ancestors of SARS-CoV-2 remain elusive. Here, we discovered a new SARS-CoV-2-related virus in Yunnan province, in 2018, provisionally named PrC31, which shares 90.7% and 92.0% nucleotide identities with SARS-CoV-2 and the bat SARSr-CoV ZC45, respectively. Sequence alignment revealed that several genomic regions shared strong identity with SARS-CoV-2, phylogenetic analysis supported that PrC31 shares a common ancestor with SARS-CoV-2. The receptor binding domain of PrC31 showed only 64.2% amino acid identity with SARS-CoV-2. Recombination analysis revealed that PrC31 underwent multiple complex recombination events within the SARS-CoV and SARS-CoV-2 sub-lineages, indicating the evolution of PrC31 from yet-to-be-identified intermediate recombination strains. Combination with previous studies revealed that the beta-CoVs may possess more complicated recombination mechanism. The discovery of PrC31 supports that bats are the natural hosts of SARS-CoV-2.
