Enhancer sequence properties remain conserved across diverse mammals after controlling for both GC-content and repetitive elements.

The heat maps give the cross-species relative auROCs for SVM classifiers trained on 5-mer spectra to identify enhancers in the species along the x-axis, and then used to predict enhancers in the species on the y-axis. The “negative” training regions from the genomic background were matched to the enhancers’: (a) GC-content, and (b) GC-content and proportion overlap with repetitive elements.