Enhancers were defined as being specifically expressed in one blood cell type if having a pairwise log2 fold change >1.5 with respect to the other four blood cell types. The fold change was calculated based on the mean expression over triplicate samples per cell type. Footprints for DNase I hypersensitivity (DHS), H3K4me1 and H3K27ac were calculated per cell type-specific enhancer set and cell type by extension of reads to 200 bp and overlap aggregation for a window of +/− 1kb around enhancer midpoint as the mean TPM signal over all enhancers in that specific subset.
