Limited evolutionary conservation of transcription factor binding regions. (A) Gray bars show the percentage of binding regions that are conserved based on either an overlap with a phastCons conserved element (left panel) or the presence of a conserved binding motif (right panel). ESR1 is the ESR1 ChIP-paired-end diTag (ChIP-PET) data set (Lin et al. 2007) while ESR1-CC is the ESR1 ChIP-chip data set (Carroll et al. 2006). Conservation levels expected by chance are shown in white and are computed from simulated binding data sets (see Methods). (B) Gray bars show the percentage of binding regions for ESR1, MYC, and CTCF that have a conserved binding motif where the regions are further partitioned into four categories: adjacent (within 250 bp of the coding region of a gene), proximal (within 5 kbp of a coding region), distant (intragenic or within 100 kbp of a gene), or desert (>100 kbp from any gene). Conservation levels expected by chance are shown in white. Error bars, 1 SD.
