Specialization Can Drive the Evolution of Modularity
Figure 5
Maximal fitness increases faster when co-option of existing gene activity states is possible.
(A,B) Black and white squares represent inactive and active genes, respectively. (A) Networks first attained activity patterns I, II and III after 3,000 generations of evolution. The selection regime promotes the evolution of modules containing genes 0–4 on one hand, and genes 5–9 on the other. (B) After 3,000 generations, selection favored gene activity pattern IV, which is a combination of activity patterns matching those of previously evolved modules, as indicated by the background colors. (C) Networks selected to attain a fourth activity pattern increase their fitness much faster if this pattern is IV, than if it is a randomly chosen activity pattern. The length of bars indicates one standard error.