AlignMCL: Comparative analysis of protein interaction networks through Markov clustering

Evolutionary analysis and comparison of biological networks may result in the identification of conserved mechanism between species as well as conserved modules, such as protein complexes and pathways. Following an holistic philosophy several algorithms, known as network alignment algorithms, have been proposed recently as counterpart of sequence and structure alignment algorithms, to unravel relations between different species at the interactome level. In this work we present AlignMCL, a local alignment algorithm for the identification of conserved subnetworks in different species. As many other existing tools, AlignMCL is based on the idea of merging many protein interaction networks in a single alignment graph and subsequently mining it to identify potentially conserved subnetworks. In order to asses AlignMCL we compared it to the state of the art local alignment algorithms over a rather extensive and updated dataset. Finally, to improve the usability of our tool we developed a Cytoscape plugin, AlignMCL, that offers a graphical user interface to an MCL engine.