A module tree of Wnt signal transduction pathways

Wnt signal transduction pathway (Wnt STP) is a crucial intracellular pathway mainly due to its participation in important biological functions, i.e., embryonic development, and stem-cell management among others as well as in human pathology, mainly cancer. For these very reasons, Wnt STP is one of the highest researched signal transduction pathways. Study and analysis of its origin, expansion and gradual development to the present state as seen in human beings is one facet of this multi-pronged research. Development of the Wnt signal transduction pathway in cellular environment among various species is not clear till date. A phylogenetic tree obtained from Wnt STPs of multiple species is one of the ways to handle this problem. In this respect, we propose a new idea of constructing a phylogenetic tree from modules of Wnt STPs of diverse species. We term it as the `Module Tree'. A module is nothing but a self-sufficient minimally-dependent subset of the original Wnt STP. Authenticity of the module tree is tested by comparing it with the two reference trees. It performs better than an alternative phylogenetic tree constructed from pathway topology of Wnt STPs.