Cross-species comparison showing that SDs next to the WBS locus have inserted at topological domain borders. Hi-C interactions and topological domains in the human fetal fibroblast cell line IMR90 are shown in dark green in the upper part as triangle view and bars, respectively. SDs with sequence similarity of 98%-99% and above 99%, respectively, (shown in yellow and orange in the SDs track) coincide with gaps within the Hi-C data. SD distribution and Hi-C data of the corresponding region in mouse are given in the lower part of the image. The position of FKBP6 and WBSCR16, the human orthologues of the two genes next to the murine topological domain borders are highlighted in green and red, respectively. The intervals commonly affected in WBS and the distal 7q11.23 syndrome are indicated by pale red bars. Note that the region distal to SRRM3 including the distal SD block are homologous to a different mouse chromosome.