Edge conservation across species. (a) Types of conservation. We denote one species as the query species (species A, left) and the other as the reference species (B, right). Shaded groups of nodes represent modules. Nodes connected by a grey line between the species represent orthologous genes. The bold black edge in the upper module of both species is a within-module conservation edge. The purple edge connecting the two modules of species A is a between-modules conserved edge. The blue edge (upper module of species A) is an extended-module conserved edge as both proteins connected by this edge are in the same module in species B. (b) Conservation of the integrated network across all pairwise comparisons. Orange bars and blue bars represent within and between conservation rates respectively. Gray bars represent conservation statistics for random modules with error bars showing the standard deviation for 1000 random runs.