Regional differences in chromatin accessibility. Accessibility profiles of individual tagged domains and a whole-embryo control at the locus of giant (gt), a gene of the AP patterning network of the gap class. Tracks show normalized coverage of 1- to 100-bp ATAC-seq fragments, smoothed over a sliding window of 15 bp. AP positions of the profiled domains are indicated schematically on the left (green shading). Blue bars and underlying shaded regions indicate coordinates of known giant enhancers (REDfly names and references provided in Supplemental Table S8). Spatial activity of each enhancer in blastoderm embryos is illustrated above (RNA in situ hybridization of a reporter gene) (reprinted from Schroeder et al. 2004). Note that gt_(-2)_broad was used as a driver of UNC84-3×FLAG in D7, and the additional copy in attP2 partially contributes to its elevated ATAC-seq signal (as discussed in Supplemental Methods). Genomic coordinates and gene models: FlyBase Release 5.57 (Gramates et al. 2017).