Building Phylogenetic Trees Based On Metabolic Networks

Phylogenetics has been investigated for several decades. Now, most of these studies perform a phylogenetic analysis of DNA or protein sequences to study the evolutionary history of organisms from bacteria to humans. These methods lead to a phylogenetic tree in which the nodes represent different species and the edges represent evolutionary relationships. For the insufficient data of gene sequences, comparative analysis of metabolic networks in different genomes can give insights into the understanding of evolutionary and organizational relationships among species. The topological structure of metabolic networks can be represented as enzyme-enzyme relational graphs. It was presented a new technique to obtain the distance of different graphs. A distance measure between graphs is defined using the similarity between nodes of graphs and the structural relationship between them. Using this approach, networks and group of networks of different organisms are compared to each other and the resulting distance matrix is used to obtain a phylogenetic tree. Apply the method to the Citric Acid Cycle metabolic networks of different organisms. Phylogenetic trees obtained form the experiments are close to existing phylogenies and reveal evolutionary relationships among organisms.