The QPD duplication spans the sub-TAD boundary separating PLAU and ENH_QPD. (A) Hi-C interaction matrix from K562 erythroid leukemia cells. Green tracks show K562 CTCF ChIP-seq and ChIA-PET interactions. Arrowhead marks a corner-dot feature, indicative of a looping interaction. A graphic interpretation (right) of the sub-TAD structures. Domains are color coded corresponding to structures marked on the Hi-C interaction matrix: blue, sub-TAD_PLAU; yellow, sub-TAD_VCL. CTCF sites are shown in purple. (B) Zoom-in of the highlighted region in panel A. K562 CTCF ChIP-seq ChIA-PET interactions (top) as in panel A. Blue “>” and red “<” depict forward- and reverse-oriented CTCF motifs, respectively. H3K27ac (blue) and H3K27me3 (gray) and CTCF (green) ChIP-seq tracks (bottom) from QPD and control megakaryocytes (MK), as in Figure 2. Black bar marks the region duplicated in QPD. Dashed rectangles mark the inferred inactive sub-TAD_PLAU (left) and active sub-TAD_VCL (right) domains. Arrowhead marks the position of ENH_QPD. (C) Black arcs show the megakaryocyte promoter capture Hi-C interactions reported by Javierre et al.⁵¹  Only interactions with a soft-thresholded, negative log-weighted P ≥ 5 are shown.