2.4. PCR amplification of S gene
The complete S gene was PCR-amplified from samples already known to be
FCoV-positive according to the primers in Table S1. All PCR products
were purified using the Omega Gel Kit following the manufacturer’s
instructions. They were ligated to the pMD19-T vector (TaKaRa Bio Inc.)
and transformed into DH5α competent Escherichia coli cells for
sequencing. The S sequences were assembled using SeqMan software
(version 7.0; DNASTAR).