Genomic map of clusters, PcG ChIP-on-chip data and predicted PRE/TREs. The location of each gene reported on the trx microarray is indicated with a vertical line (up-regulated genes in red, down-regulated genes in green). Genes in the forward strand are displayed above the chromosome line, genes in the reverse strand are displayed below. Clusters of genes on each experiment are indicated with a triangle in red or green according to their expression. PcG binding domains reported by Schwartz et al. , Tolhuis et al.  and Negre et al.  are displayed in blue. PRE/TRE predictions obtained by Ringrose et al.  are displayed in black.