Determining the percentage of predicted peaks associated with a motif within 50 bp of the peak center for FoxA1 and NRSF ChIP-Seq, we found MACS to give consistently higher motif occurrences (Figure 2c,d). Evaluating the average distance from peak center to motif, excluding peaks that have no motif within 150 bp of the peak center, we found that MACS predicts peaks with better spatial resolution in most cases (Figure 2e,f). For CTCF, since QuEST does not run on samples without controls, we only compared MACS to ChIPSeq Peak Finder and FindPeaks. Again, MACS gave both higher motif occurrences within 50 bp of the peak center and better spatial resolutions than other methods (Figure S1 in Additional data file 1). In general, MACS not only found more peaks with fewer false positives, but also provided better binding resolution to facilitate downstream motif discovery.
