Phylogenetic clustering of crocodilian ERVs (CERVs). Neighbor joining tree based on aligned amino acid sequences from the retroviral pro-pol gene region. The final alignment length was 799 characters including gaps. Names near the shaded regions indicate the retroviral genus to which these sequences belong. The general host species taxa are indicated by symbols. The two major clades of ERVs found in crocodilians are indicated by colored circles: CERV1 in red and CERV2 in blue. Red dots indicate additional crocodilian ERV sequences. Numbers near branches indicate bootstrap support values.