Biological networks: Comparison, conservation, and evolutionary trees (Extended abstract)

We describe a new approach for comparing cellular-biological networks, and finding conserved regions in two or more such networks. We use the length of describing one network, given the description of the other one, as a distance measure. We employ these distances as inputs for generating phylogenetic trees. Our algorithms are fast enough for generating phylogenetic tree of more than two hundreds metabolic networks that appear in KEGG. Using KEGG's metabolic networks as our starting point, we got trees that are not perfect, but are surprisingly good. We also found conserved regions among more than a dozen metabolic networks, and among two protein interaction networks. These conserved regions seem biologically relevant, proving the viability of our approach.