Fig. 3.

Limited cross-reactivity accompanies the evolution of WCI. (A) Variation of the extent of cross-reactivity with the evolution of WCI. The x axis shows the number of tasks done by the same cluster of gene products, and the y axis is the percentage of such clusters that are preforming two, three, four, and five tasks in this cross-reactive fashion. (B) Snapshot of simulation results when new tasks are introduced such that they are either closely related to tasks from an earlier era or not. Two modules of such related tasks are depicted in characteristics space. Large spheres with radius ε₂ are drawn around each task. Brown spheres show tasks being performed by single-gene products, blue spheres show closely related tasks being performed by clusters of cooperating gene products. Small spheres correspond to gene products. (C) The percentage of two tasks completed by the same gene products is high only for related tasks. Three characteristics describe the interaction characteristics of tasks and gene products.