Fig. 1.

Difference in divergence between PV (ERVs) and RM+ (selfish DNA) for chimp-human orthologues, aggregated by age. Age categories were assigned to chimp-human orthologues by identifying the most distant primate relative in which the orthologous sequence could also be found. Category CH contains ERVs detected in chimpanzee and human only (187 ERVs); category CHG contains ERVs for which gorilla was the most distant relative in which an ERV was detected (77 ERVs); category CHGO+ contains ERVs for which orangutan (70 ERVs) or macaque (2 ERVs) was the most distant relative in which an ERV was detected. (Note: whiskers estimate 95 % confidence intervals, filled dots represent median values, unfilled dots represent outliers.)