Comparative Analysis of Gene Networks in Humans and Model Organisms for Aging Studies

Aging is the cause of the loss of vitality on a day-to-day basis, a risk factor for developing chronic diseases and ultimately leading to death. This inevitable biological process is yet to be completely understood. A hypothesis states that manipulation of aging process can enable maintain physiological function and perhaps prevents age related diseases. Currently, model organisms are being used in the investigation of the genetic and molecular mechanism of the aging process. In this study, the adequacy of the major model system, the fruit fly (Drosophila melanogaster) and the rodent mouse (Mus musculus), was analyzed using Jepetto software through comparison of all the genomes of the model organisms with all the genomes of human genome by network statistics of string interactions. The software mapped the gene set of humans and the two model organisms on an interaction network and computed the gene properties by network density, centrality nodes and clustering coefficient. Of all three genomes, the human gene network is the largest and dense with the highest number of neighbors. On the other hand, the mouse and drosophila network are relatively smaller and in terms of density, the former is less dense, and the latter is sparse. The average number of neighbors of both model organisms are similar and approximately 25% of the human network. In the distance/shortest path length between the nodes, there was a decreasing order of connectivity in drosophila to mouse to human. The node with the path length 2 exhibited the highest frequency in all the organisms. In between centrality distribution, the nodes of the human network were observed to be closer. On comparison, mouse network is closer while the drosophila network is widely spread. The information spread between the nodes is measured by the closeness centrality distribution plot and the human network found to have highest closeness centrality than the other two species. Neighborhood connectivity distribution. The network clustering coefficient of genes of drosophila was much more widespread than the other two species.