FIG 8.

DnERV(Env1.1) as well as a series of vertebrate endogenous and infectious retroviruses are chimeric retroviruses with a betaretrovirus pol gene and a gammaretrovirus env gene. The phylogenetic trees were determined as described in reference 11, by using the catalytic domain sequences of the RT region of the indicated viruses (left) or the TM region of the corresponding env genes (right) by the maximum likelihood method. The horizontal branch length and bar indicate the percentages of amino acid substitutions. Percent bootstrap values (>50%) obtained from 1,000 replicates are indicated at the nodes. Blue and red indicate typical gamma- and betaretroviruses, respectively, as determined by pol phylogenetic relationships, and orange indicates beta/gamma-type chimeric retroviruses. The following sequences were used: MoMLV (GenBank accession number NC_001501.1), FeLV (accession number NC_001940.1), PERV-A (accession numbers AAM29192.1 and AEF12608.1), RD114 (accession number NC_009889.1), BaEV (accession number D10032.1), REV-A (accession number DQ387450.1), syncytin-1 (accession numbers AAB66528.1 and AF208161), TvERV(D) (accession numbers AF224725 and AF284693), SMRV (accession numbers NC_001514.1 and M23385.1), DrERV (accession numbers KP175580 and KP175581), syncytin-Ory1-ERV (accession numbers XP_008268050 and ACZ58381), SRV1 (accession number M11841.1), SRV4 (accession number NC_014474.1), MPMV (accession number NC_001550.1), MMERV-β6 (accession number NT_039167), HERV-K (accession number AY037928.1), MMTV (accession number NC_001503.1), enJSRV (accession numbers AAD45226.1 and AAF22166.1), and HIV-1 (accession number K02013).