Bayesian estimate of the phylogenies for the internal region and LTRs (those of the same element are linked by lines). Posterior probabilities for the internal region are shown above the branches except (for clarity) in the human-specific clade. Internal branches are thickened if they were also recovered in a strict consensus of the most parsimonious trees. Thick terminal branches in the LTR tree represent 5′ LTRs, and thin terminal branches represent 3′ LTRs. Boxes represent elements whose 5′ and 3′ LTRs do not cluster together, with a thick box showing that they are polyphyletic in both Bayesian and MP trees, and a thin box showing that they are paraphyletic in both, or monophyletic in one. Filled circles denote elements containing the 292-bp deletion spanning the pol-env junction [Type I HERV-K(HML2) subgroup], which is absent in all other elements [Type II HERV-K(HML2) subgroup]. The clade created by segmental duplication of the host genome is also indicated, as are the branches indicating probable changes in the distribution of elements among primates.