Phylogenetic tree showing the relationships of class II ERV sequences. A maximum likelihood tree was based on deduced amino acids of Pro-Pol fragments (Dataset 4; 236 codons). Bootstrap values >70% are indicated. Felid illustrations are shown to designate their clades. The three ERV clades mentioned in the text are highlighted by showing sequences from four of the major felid lineages: blue (from tiger belonging to the Panthera lineage), red (cat, domestic cat lineage), green (PYEM13001, from P. yagouaroundi and Puma concolor, both from the Puma lineage) and pink (L. geoffroyi, ocelot lineage). The scale bar at the bottom of the Figure represents distance in amino acid substitutions per site. Sequences retrieved from GenBank are listed in Additional file 1: Table S1.