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. 2021 Nov 20;144:190–195. doi: 10.1016/j.rvsc.2021.11.014

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Fig. 1 — The evolution of CCoVs. The probable origin of FCoV type II, CCoV type I and TGEV-like CCoV as a result of recombination events.

a) CCoV II: “classical” canine coronavirus type II; b) CCoV I: canine coronavirus type I (in yellow: the spike protein originated from feline coronavirus type I); c) FCoV I: feline coronavirus type I; d) FCoV type II: feline coronavirus type II (in red: the spike protein originated from CCoV II; e) TGEV: transmissible gastroenteritis virus of swine (in red: the spike protein originated from CCoV II; f) TGEV-like: TGEV-like canine coronavirus (in green: the spike protein originated from CCoV II). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)