Figure 7
From: Porcine circovirus type 2 (PCV2): genetic variation and newly emerging genotypes in China
Phylogenetic trees based on 175 PCV2 full-length sequences, including the 19 isolates from this study and 156 strains submitted to GenBank. The accession numbers for these strains are indicated and some branches in the tree are collapsed in the form of black triangles, followed by their corresponding accession numbers. The tree was constructed using a neighbor-joining algorithm with the MEGA 4 software. Three main genotypes (PCV2a, PCV2b and PCV2c), along with a newly emerging genotype PCV2d, were identified by multiple alignments, and PCV2b was subdivided into two clusters. Genotype PCV2b was predominant among strains in China. Three PCV2d isolates from this study form a single branch, marked by a red box. Two PCV2a isolates from this study (marked by a pink circle) were separated from the other Chinese PCV2a isolates and were instead located at a mixed branch with strains from Taiwan, Japan and Europe (underlined in green).