3.2 Genome characterization of PiCV genomes
A total of sixty-seven full genome sequences were obtained and deposited in GenBank with accession numbers: MW181925 to MW181991 (Table S2). The assembled circular whole genome sequences were detected as eleven sizes ranging from 2030 to 2045 nt with their cap gene ranging from 813 to 828 nt in length and rep gene of 948 or 954 nt as shown in Table S2. Among these variable genome length, the most common genome sizes were 2037 (n=21) and 2042 (n=13) nucleotides, respectively (Table S2). The sequence comparison among the 67 identified PiCV strains revealed nucleotide homologies of 84.2%–100% and these sequences exhibited nucleotide homologies of 83.0%–97.8% and 82.0%–98.3% as compared with Chinese PiCV reference strains and the ones from the other countries (Table S3). In particular, four unique nucleotide substitution (CG-GCGA) was found in the intergenic region between rep andcap stop codons of two strains (SX1/SN/2017/MW181932 and YB4/SN/2018/MW181981) compared with all reference strains.