Luis P Villarreal

Professor Emeritus, Department of Molecular Biology and Biochemistry, School of Biological Sciences; University of California, Irvine

Villarreal has long been interested in virus-host interactions, especially with regard to viruses that persist either in the genomes or epigenomes of their host. For the last 20 years, he has focused his study on the general role of virus evolution on Life. In the last decade metagenomic assessments of various habitats have led us to realize that viruses are the dominate biological entities of the biosphere and are the most numerous, diverse and dynamic genetic agents on Earth. Viruses have had major influence on the genesis and evolution of life.

Although viruses have long been dismissed from the Tree of Life a simply destructive and selfish extra-genomic genetic parasites, comparative genomics now makes it clear that viral colonization distinguishes all domains of life. I have been pursuing how and why some viruses (and their defective relatives, transposons) are able to stably persist in their host and sometimes become a colonizer of the host genome. The ability of a virus to persist is a transforming event for host population survival and requires specific mechanisms and strategies (such as addiction modules). These viral derived mechanisms, however, provide new mechanisms of immunity and identity for the host. I am now tracing how viruses have contributed to host group survival from bacteria to recent human social evolution.

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"Viruses are competent in all forms of biological code (genetic and epigenetic). Viruses are also able to adapt at rates up to a million fold faster then that of their host. And virus code has clearly modified and added to all forms of host code. Thus viruses are major editors of host code. But such action is not Darwinian (from the common ancestor). No life form can be considered fit unless in the context of its virosphere/habitat. The presence of a defective virus in host, is evidence of virosphere adaptation. As genetic parasites, viruses depend on others (i.e. host, other virus) for their reproduction. But this very dependence makes them agents of cooperation. And their capacity for transmission makes them agents of social interactions."

(Luis Villarreal)

Origin of Group Identity: Viruses, addiction and cooperation

From bacteria to humans, all life has ways to recognize themselves and differentiate themselves from similar life forms. The ability to recognize similarity can be called group identity or group membership and also relates to group cooperation. Even viruses have the capacity for group identity and cooperation. However, those viruses that stably colonize bacteria can directly affect the group identity of their host. Starting with this virus-host relationship, this book traces the origin and evolution of group identity. By examining the stable, extrachromosomal viruses of bacteria, a strategy has been defined that is used for both virus persistence and group identity; this is the addiction module of phage P1. Thus, this book examines how genetic parasites and addiction modules have been involved in the origin of toxins/antitoxins modules as systems of group identity and immunity. The origin of sensory systems for light and small molecule (pheromone) detection and production, social motility, and programmed cell death are all examined. From the emergence of worms with brains, to vertebrate fish, to insects and tetrapods, olfaction and pheromones were maintained for group identity purposes and linked to addictive social bonding. In the African primates and humans, however, a great colonization by genetic parasites mostly destroyed this pheromone based system of social identity. This compelled primates to evolve enlarged social brains that used vision to learn group identity. Humans additionally evolved an even larger social brain and also developed a mind able to learned language and beliefs to specify group identity.
Viruses and the Evolution of Life

While it is generally accepted among evolutionary biologists that viruses are not self-sustaining and therefore cannot be alive, their impact on life is dramatic. Starting with prebiotic precursors of life, the book features an engaging discussion of various life forms and how each group has been affected by viruses. The author develops the concept of and distinction between acute and persisting viruses, an area of study that has heretofore largely been ignored. The relationship between the familiar disease-causing viruses and those viruses from which they emerge is also clarified.

Selected Publication

“Persistent virus and addiction modules: an engine of symbiosis.” Villarreal, Luis P. Current opinion in microbiology 31 (2016): 70-79. Link

“Viruses and the placenta: the essential virus first view.” Villarreal, Luis P. Apmis 124.1-2 (2016): 20-30. Link

“Force for ancient and recent life: viral and stem-loop RNA consortia promote life” Villarreal LP, Ann N Y; Acad Sci. 2014 Nov 6. doi: 10.1111/nyas.12565. [Epub ahead of print] PMID: 25376951 Link

“Rethinking quasispecies theory: From fittest type to cooperative consortia” Villarreal LP, Witzany G.;
World J Biol Chem. 2013 Nov 26;4(4):79-90. doi: 10.4331/wjbc.v4.i4.79. Review. PMID: 24340131 Link

“Phycodnavirus potassium ion channel proteins question the virus molecular piracy hypothesis”;Hamacher K, Greiner T, Ogata H, Van Etten JL, Gebhardt M, Villarreal LP, Cosentino C, Moroni A, Thiel G.;PLoS One. 2012;7(6):e38826. doi: 10.1371/journal.pone.0038826. Epub 2012 Jun 7. PMID: 22685610 Link

“Viral ancestors of antiviral systems” Villarreal LP.; Viruses. 2011 Oct;3(10):1933-58. doi: 10.3390/v3101933. Epub 2011 Oct 20. Review. PMID: 22069523 Link

“The source of self: genetic parasites and the origin of adaptive immunity” Villarreal LP., Ann N Y; Acad Sci. 2009 Oct;1178:194-232. doi: 10.1111/j.1749-6632.2009.05020.x. PMID: 19845639 Link

“Viruses are essential agents within the roots and stem of the tree of life” Villarreal LP, Witzany G.;J Theor Biol. 2010 Feb 21;262(4):698-710. doi: 10.1016/j.jtbi.2009.10.014. Epub 2009; Oct 13. PMID: 19833132 Link

“Persistence pays: how viruses promote host group survival” Villarreal LP.,Curr Opin; Microbiol. 2009 Aug;12(4):467-72. doi: 10.1016/j.mib.2009.06.014. Epub 2009 Jul 14. Review. PMID: 19608458 Link

“Are viruses alive?” Villarreal LP. Sci Am. 2004 Dec;291(6):100-5. PMID: 15597986 Link
Complete list of publications

For a complete list of publications, click here.

Luis P Villarreal

Professor Emeritus, Department of Molecular Biology and Biochemistry, School of Biological Sciences; University of California, Irvine

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Books

Origin of Group Identity: Viruses, addiction and cooperation

Viruses and the Evolution of Life

Publications

Selected Publication

Complete list of publications

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