Clustering TAL1 OSs based on epigenetic features. (A) TAL1 OSs clustered by the ChIP-seq signals of H3K4me1 and H3K4me3 (log2 of the ratio), TAL1, and GATA1 (k-means clusters, k = 8). (B) Enhancer activities of TAL1 OSs tested by transient transfection assays in K562 cells, grouped in clusters by epigenetic features. The names of individual TAL1 OSs are given along the x-axis, and the percent active in each cluster is listed. The distinctive properties of each TAL1 OS cluster are summarized in the three colored bars, derived from Figure 2A. (C) Activities of TAL1 OSs grouped in clusters by epigenetic features, shown for both enhancer assays: transient transfection into K562 cells (left) and transgenic mice at E11.5 (right).