S gene recombination. (A) Diagram showing the full-length S gene of PEDV virulent CV777 and the corresponding regions encoding Domain 0, S1 domain, S2 domain, transmembrane domain (TM), and a short cytoplasmic tail (CT). The S1 domain is composed of four subdomains including S1-NTD (S1 N-terminal domain), S1-CTD (S1 C-terminal domain), SD-1, and SD-2. (B) Schematic representation of potential recombination events listed in Table 1. The recombination event serial number and the description of potential recombinants (GenBank ID: virus name/country-collection year) are show on the left. The filled pink and green blocks represent the DNA regions from minor or major parent viruses, respectively. The numbers on the top of filled green blocks indicate the nucleotide positions of breakpoints relative to the spike gene sequence of corresponding recombinant viruses on the left.