Figure 3. . . Phylogenetic tree based on partial amino acid sequences (aa 1056–1069) of the spike proteins of 118 feline infectious peritonitis viruses (FIPVs) and 183 feline enteric coronaviruses (FECVs) obtained by using reverse transcription nested PCR and sequencing of the distinguishing genomic region. A circular rooted neighbor-joining tree was constructed by using the bootstrap method and applying 1,000 replicates. Black dots indicate FIPVs. Clade A comprises FIPVs containing the M1058L mutation; clade B comprises FIPVs containing the S1060A mutation.
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