Introduction: Regarding SARS-CoV-2, the coronavirus RaTG13 of the brown bat (Rhinolophs affinis) is a potential ancestor.Their genomes have 97.41% identity ; however, at least five amino acid (aa) substitutions (
F486L,
Q493Y,
S494R,
N501D, and
Y505H) at critical sites of the
Spike (
S) glycoprotein receptor-binding domain (
RBD) of RaTG13 are crucial for the Wuhan-SARS-CoV-2 lineage to acquire high tropism with its cognate human cell receptor (cell-surface peptidase angiotensin-converting enzyme 2, ACE2).
Introduction: The first strain of SARS-CoV-2 identified in Wuhan, China, in December 2019, was also characterized as having five critical amino acid differences in its
RBD when