Figure 5. Phylogenetic relationships among simian retroviruses and SRV-4 detected in Japanese macaques at KUPRI.

A phylogenetic tree was constructed from the partial gag sequences (514 bp) using the neighbor-joining method. The phylogenetic tree was evaluated using a bootstrap test based on 1,000 resamplings. The sequence of simian endogenous retrovirus was used as an outgroup to indicate the location of the root of the ingroup. The tree indicates that the SRV from Japanese macaques clustered with the SRV-4 strains isolated in Texas and California, USA, and Tsukuba, Japan. Numbers on the nodes represent bootstrap values. Scale bar represents the evolutionary distances.