Figure 3

Conceptual coding schemes for the assignment of binding sequences to TFs. Binding sequences are displayed as points, TFs as colored spheres. Colors correspond to the biological function of each TF. a) A sphere-packing code – code-words are covered by non-overlapping spheres. The TFs do not share binding sequences. b) A smooth code – code-words are covered by overlapping spheres with similar function. TFs can share binding sequences with neighbor TFs. This type of code is predicted to be smooth, that is where TFs with shared binding sequences tend to have similar biological function, represented by spheres of similar color in the figure.