The WashU Epigenome Browser combines advanced web technology with intuitive graphical design to visualize long-range interaction data. Pairs of interacting regions can be joined by arcs (Figure 1b, 1c), or indicated by filled rectangles in a heatmap (Figure 1d). The “arc” glyph is suitable to represent sparse interactions (as is common with ChIA-PET, and sometimes found in 5C data sets), and the “heatmap” glyph is best for dense interactions (as is typical for Hi-C and some regions in 5C data sets). The data tracks are interactive: investigators can click on the arcs or heatmap cells to invoke a companion Browser panel (Supplementary Fig. 1), which displays epigenomic data over the distal interacting locus. This companion panel can be navigated independently, enabling comparison of data patterns of interacting loci in the same view. Thus, investigators can observe several loci that are distant in their genomic coordinates but are inferred to be spatially close to each other in the nucleus. Both the “arc” and “heatmap” modes only display interactions that are contained within the current browsing range while omitting interactions beyond the
