Concept Paper
Version 1
This version is not peer-reviewed
All Viruses are Unconventional
Version 1
: Received: 18 September 2020 / Approved: 19 September 2020 / Online: 19 September 2020 (03:51:15 CEST)
How to cite: Claverie, J. All Viruses are Unconventional. Preprints 2020, 2020090445 Claverie, J. All Viruses are Unconventional. Preprints 2020, 2020090445
Abstract
The extension of virology beyond its traditional medical, veterinary or agricultural applications, now called environmental virology, has shown that viruses are both the most numerous and diverse biological entities on earth. In particular, virus isolation studies involving unicellular eukaryotic hosts (heterotrophic and photosynthetic protozoans) revealed numerous viral types previously unexpected in terms of virion structure and morphology, genome size and gene content, or mode of replication. Complemented by large-scale metagenomic analyzes, these discoveries have rekindled interest in the enigma of the evolutionary origin of viruses, for which no simple definition encompassing all of their diversity is still unanimous. Several laboratories have repeatedly tackled the deep reconstruction of the evolutionary history of viruses, using various methods of molecular phylogeny applied to the few shared genes detected in certain virus groups (e.g. the Nucleocytoviricota). Beyond the practical difficulties of establishing reliable homology relationships from extremely divergent sequences, I present here purely conceptual arguments highlighting several fundamental limitations plaguing the reconstruction of the deep evolutionary history of viruses, and even more the identification of their unique of multiple origin (s). Those limitations are direct consequences of the particularly random mechanisms which govern the reductive evolution of obligate intracellular parasites.
Keywords
origin of viruses; phylogenetic reconstruction; reductive evolution; obligate intracellular parasites; Varidnaviria; Bamfordvirae; Nucleocytoviricota
Subject
Biology and Life Sciences, Virology
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Comments (0)
We encourage comments and feedback from a broad range of readers. See criteria for comments and our Diversity statement.
Leave a public commentSend a private comment to the author(s)
* All users must log in before leaving a comment
