The Global Organization and Topological Properties of Drosophila melanogaster

by Rajarathinam, Thanigaimani

The fundamental principles governing the natural phenomena of life is one of the critical issues receiving due importance in recent years. Most complex real-world systems are found to have a similar networking model that manages their behavioral pattern. Recent scientific discoveries have furnished evidence that most real world networks follow a scale-free architecture. A number of research efforts are in progress to facilitate the learning of valuable information by recognizing the underlying reality in the vast amount of genomic data that is becoming available. A key feature of scale-free architecture is the vitality of the highly connected nodes (hubs). This project focuses on the multi-cellular organism Drosophila melanogaster, an established model system for human biology. The major objective is to analyze the protein-protein interaction and the metabolic network of the organism to consider the architectural patterns and the consequence of removal of hubs on the topological parameters of the two interaction networks.

Analysis shows that both interaction networks pursue a scale-free model establishing the fact that real networks from varied situations conform to the small world pattern. Similarly, the topology of the two networks suffers drastic variations on the removal of the hubs. It is found that the topological parameters of average path length and diameter show a two-fold and three-fold increase on the deletion of hubs for the protein-protein interaction and metabolic interaction network, respectively. The arbitrary exclusion of the nodes does not show any remarkable disparity in the topological parameters of the two networks. This aberrant behavior for the two cases underscores the significance of the most linked nodes to the natural topology of the networks.