Figure 3.

Expansion and multiple inversions of the 16p12.1 region in humans and the syntenic regions in non-human primates during primate evolution. The genomic organization is compared within a generally accepted phylogeny of macaque, orangutan, gorilla, chimpanzee and human. The region has expanded from 726 kbp (macaque) to 1.6 Mbp (human S2) as a result of segmental duplication accumulation (black and colored rectangles). Sequence and FISH data indicate that the inverted configuration as found in orangutan and macaque is likely the ancestral state in all mammals (I). The expansion of segmental duplications in the African great ape ancestor occurred in conjunction with two inversions between BP1 to BP2 (green arrow) and BP2 to BP3 (red arrow), which may have reverted back to the direct orientation in the chimpanzee lineage (II). The region has become increasingly complex in human leading to the addition of another polymorphic 333 kbp at BP1 specifically in the human lineage (III). Colored boxes indicate segmental duplications as determined by complete sequencing of large-insert BAC clones from primate genomic libraries (Supplementary Note).