Understanding the origins of SARS-CoV-2 is critical for deterring future zoonosis,
discovering new drugs, and developing a vaccine. We show evidence of strong purifying
selection around the receptor binding motif (RBM) in the spike and other genes among bat,
pangolin, and human coronaviruses, suggesting similar evolutionary constraints in different
host species. We also demonstrate that SARS-CoV-2's entire RBM was introduced through …