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Title:Origin of viruses revealed by the genomic study of protein domain structures
Author(s):Nasir, Arshan
Advisor(s):Caetano-Anolles, Gustavo
Department / Program:Crop Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
phylogenomics, protein domain, structure, evolution
Abstract:The discovery of giant viruses with complex proteomes, remnants of translation machinery and virus-specific parasites have raised important questions about their origin. Evidence advocates for their inclusion into global phylogenomic studies and their consideration as a distinct and ancient form of life. Here we reconstruct phylogenies describing the evolution of proteomes and protein domain structures of viruses and cells that define viruses as a ‘fourth supergroup’ along with cellular superkingdoms Archaea, Bacteria, and Eukarya. Universal trees of life (uToLs) place viruses at their root and trees of domains indicate they have evolved via massive reductive evolutionary processes. Since viral domains are widespread among cellular proteomes we propose that viruses mediate gene transfer between cellular species and crucially enhance biodiversity. Results call for a change in the way viruses are perceived. They likely represent a distinct and most ancient form of life and a very crucial part of our planet’s biosphere. Additionally, we assign functions to molecular structures in nearly a thousand proteomes and highlight the conserved nature of cellular proteomes.
Issue Date:2012-09-18
Rights Information:Copyright 2012 Arshan Nasir. Chapter 3 copyright 2011 IEEE. In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of the University of Illinois's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to to learn how to obtain a License from RightsLink.
Date Available in IDEALS:2012-09-18
Date Deposited:2012-08

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