Representative unrooted Pol neighbor joining (NJ) dendrogram. Unrooted Pol neighbor joining (NJ) dendrogram (500 bootstraps consensus) of the seven retroviral genera: alpha-, beta-, gamma-, delta-, epsilon-, lenti- and spuma-like retroviruses. The somewhat more loosely defined (endogenous) retroviral classes are indicated in the periphery. The various host species are indicated with symbols next to each taxonomic unit. The novel sequences are named according to their chromosomal positions within respective genomes. (hg15 and 16: Human genome; gg01: Chicken genome and pt01: chimpanzee genome). The two pt01 sequences were unique to chimpanzee and not found in humans [Jern et al. submitted].