Phylogenetic profiles of interaction patterns. Normalized histograms of the evolutionary fragility of interaction patterns belonging to the following three classes are shown: instances of network motifs (red); generic patterns of interacting genes, irrespective of their abundance (black); patterns composed of genes taken at random (white). The five possible values (in increasing value 0 to 4) of the evolutionary fragility are reported on the abscissa. A small fragility value indicates that all the genes composing the interaction patterns tend to co-occur in the other genomes compared and point to evolutionary pressure acting to preserve the interaction pattern.
Mazurie et al. Genome Biology 2005 6:R35 doi:10.1186/gb-2005-6-4-r35