Most frequently the risk of harmful consequences in the event of the reintroduction of a variant virus after its adaptation to the ACE2 from a different species is low because the mutation or mutations are very likely to have “host-specific signatures.” According to the quasispecies evolutionary model, these mutations do not predate the new host infection and can be considered specific to the host and advantageous for the virus mainly in this host species (Woo et al., 2012; Frutos and Devaux, 2020). The gene discussed is ACE2; the disease is infection.