A Protein-Protein Interaction Network of Segmentally Duplicated Genes in Humans: A Molecular Systems Insight to the Origin of Human Intelligence

Abstract

Segmentally duplicated regions are stretches of DNA in the human genome that have been copied several times. They are said to be the driving force of evolution. Because of this, it is important to study the different proteins that are coded in these regions and elucidate their interaction with other proteins. Protein-protein interactions are integral to the cellular mechanisms that govern the biological processes of the human body. In this study, proteins of human segmentally duplicated regions were retrieved from the Human Genome Segmental Duplication Database. Twenty-three (23) proteins were obtained and were individually inputted in Human Protein Reference Database and BioGPS to retrieve protein information and their interactions. Proteins obtained are of the following molecular classes: phototransferase, nucleotidyltransferase, myristoyltransferase, G-protein coupled receptor, transcription factor and neuropeptide. Some of the proteins however are unclassified and their functions are still unknown. Cytoscape was used to manually construct a network in order to visualize the protein-protein interactions. Proteins interact with each other to efficiently carry out their function. Most of the proteins found in the human segmentally duplicated regions are also found in lower life forms but some exhibit different specific functions and differ in areas where they are localized. Most of the proteins also are highly conserved throughout evolution and some are products of duplication events, consistent with the fact that they are found in the segmentally duplicated regions. Several proteins are also found to have been involved in the development of the brain during evolution.