(A) Feature weights. (Green) Positive weights learned by the classifier; (brown) negative weights. Motif features of the same TF are clubbed together. The names of the features are listed near the baseline of the graph. (*) Features known previously to be implicated in heart activity or heart development; (?) de novo motifs A–E. (B) The five de novo motifs with positive weights. STAMP (Mahony and Benos 2007) was used to predict de novo motif associations with binding specificities of TF families from TRANSFAC and JASPAR. The top match with its P-value is shown. The last column indicates the fraction of sequences in the enhancer and the control set containing a match to each de novo motif.