Evolving sets of HoxB4 targets during ESC differentiation to hematopoietic cells. (A) Evolving functional categories enriched among Hoxb4 targets during the differentiation process. Genomic coordinate Hoxb4 binding peaks were used as input to the GREAT algorithm⁴⁶  for gene ontology term enrichment analysis. D6, D16, and D26 indicate Hoxb4 peaks uniquely observed in day 6, 16, 26 cells, respectively; D16/D26, Hoxb4 peaks shared uniquely by day 16 and 26 cells; red, gene ontology term enriched at FDR = 0.05; black, gene ontology term not enriched. Dendrogram was clustered using hierarchical clustering. (B) Median expression levels of the sets of genes enriched at different time points reported in panel A. Only subsets of genes that were differentially expressed and targeted by HoxB4 at specific time points in panel A were used for the plot.