Figure 1From: Statistical tests for natural selection on regulatory regions based on the strength of transcription factor binding sitesChanges in binding site strength in the absence of selection. a) shows time courses for the strength of a transcription factor binding site (S) in a simulation of evolution without selection. The strength of a real binding site (dotted trace) usually decreases from the strength expected for real binding sites (E[S|motif]) to that expected under background residue frequencies (E[S|bg]). An example of a binding site created from background sequence in the absence of selection (solid trace) is also shown. b) shows the probability (p) of observing a change in score of size ΔS given than a sequence is a binding site (dotted trace) or a background sequence (solid trace).Back to article page