PING
Check out # 4.
(necessary for the virus go open the ACE2 receptor and get into human cells, and no related coronaviruses have it, just COVID);
further, that the spike is coded for by a 12-codon INSERT;
last that the spike has two copies of the amino acid arginine in a row;
but the codons in the virus which tell them to appear,
are the codons most often used by humans to code for arginine, and not by coronaviruses.
Nobel Prize winner David Baltimore (and IIRC, former President of CalTehc) called that a "smoking gun".