a, In silico deletion of GATA4 was significantly more deleterious to previously reported GATA4 direct targets33 than to housekeeping genes, previously reported NOTCH1 targets4, previously reported NKX2–5 targets46, or GATA4 indirect targets33 (*p<0.05 Wilcoxon, FDR-corrected; center line=median, box limits=upper and lower quartiles, whiskers=1.5x interquartile range, points=outliers). b, In silico deletion of GATA4 or TBX5 alone was significantly more deleterious to previously reported GATA4/TBX5 co-bound targets33 than to housekeeping genes; in silico deletion of the combination of GATA4 and TBX5 was even more deleterious to co-bound targets, significantly more than to housekeeping genes and significantly more than the sum of the effect of GATA4 or TBX5 alone on co-bound targets (*p<0.05 Wilcoxon, FDR-corrected).