A model for the acquisition and dispersal of 2p11 duplicons. An expanded two-step model is shown to explain the current organization of 2p11. First, a burst of DNA duplicative transposition events occurs in the common ancestor of humans and apes (10–20 Myr), creating a large mosaic region consisting of at least 14 duplicons. During the radiation of humans and African great-apes (4–8 Mya), a series of secondary duplications disperse larger cassettes to other pericentromeric regions, leading to quantitative and qualitative differences of each larger block within different lineages. More recent transposition events suddenly cease or are no longer fixed during this second phase.
