Quantification of CRE function (median from three biological replicates). Activity: reporter expression (exp. = average normalized mBC UMI count) in the maximum-expression cell type (defined from fine clusters of Extended Data Fig. 4a ). Specificity: maximum-expression cell-type reporter level over expression in all other cells. Active elements (black: nonspecific, distal; orange: nonspecific, <1 kb TSS; red: cell type specific) show excess expression (bootstrap resampling) in all replicates compared to basal controls (no and minimal promoter). Cell-type-specific elements (specificity >5 and significantly higher than cell-type permuted sets) are highlighted (red). CRE Lamc1 :chr1_1218, active in two cell types, is marked with a star. Exogenous promoters (same as Fig. 2a ) are shown as colored squares.
