Fig. 1

The tripartite graph for an intuitive interpretation of the generative process. Rectangular nodes represent the GO terms, and rounded nodes represent all genes annotated in one species. An edge is introduced between a GO term and a gene node, if and only if the gene is annotated by that term. The edges between two gene nodes are the counterpart edges in a biological network. The different line types represent different connection types: active-active, active-inactive, inactive-inactive