Figure 1

Maximum likelihood phylogenetic trees based on the amino acid sequence alignment of the DNA polymerase genes from various poxviruses. Multiple sequence alignment was performed with MUSCLE and the appropriate phylogenetic model was selected using ProtTest 2.4. The maximum likelihood phylogenetic tree based on the JTT matrix-based model (121) with 100 bootstrap replicates were performed in MEGA 5.10. Discrete Gamma distribution was used to model evolutionary rate differences among sites. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. All positions containing gaps and missing data were eliminated.