RTRs of Myc and NFΚB in simulated promoter sequences. The x-axis denotes evolutionary divergence measured by the number of substitutions per site, and the y-axis denotes the RTR of a TFBS in a descendent sequence. The figure shows that the predicted values (lines) from the exponential model given in equation 2 fit well with observed RTR values (points) from an evolution simulation of (a) Myc and (b) NFΚB.
Huang et al. Genome Biology 2007 8:R225 doi:10.1186/gb-2007-8-10-r225