Fig. 1.

A) Timeline of the emergence of coronaviruses (CoVs) and their classification, functional receptor, and hosts. B) Phylogenetic analysis of 13 sequences from selected CoVs including α-CoVs: HCoV-229E (GenBank ID: KF514433.1) and HCoV-NL63 (KF530114); β-CoVs: HCoV-OC43 (AY391777), HCoV-HKU1 (NC_006577.2), MERS-CoV (NC_019843), SARS-CoV (NC_004718.3), SARS-CoV2 (NC_019843), bat-SL-CoVZXC21 (MG772934), and bat CoV HKU9-1 (EF065513); γ-CoVs: SW1 (NC_010646), and IBV (NC_001451.1); and δ-CoVs: HKU17 (YP_005352845) and HKU11 (YP_002308478.1).