IAS BMVP Eugene V. Koonin Lecture 'Evolution of the virus world and antivirus defense: a tangled web'

11 October 2017, 1.00 PM - 11 October 2017, 2.00 PM

Dr Eugene Koonin, National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, Maryland,USA

Seminar room G13/G14, Life Sciences Building

Dr Koonin is the most prominent, contemporary computational biologist, and one of the most important evolutionary biologists of our time.

Viruses and virus-like parasitic genetic elements are ubiquitous satellites of all cellular life and the most common biological entities on earth, in terms of both physical abundance and genetic diversity. Population-genetic models of genome evolution imply that persistence of genomic parasites is virtually inevitable in the long term. Despite their essential relationships with cells, the parasitic elements comprise a semi-autonomous ‘Virus World’ that apparently coexisted with cellular life since its inception and is held together by a small set of ‘Virus Hallmark Genes’. The evolution of the Virus World is best represented through a combination of traditional phylogenomics with bipartite network analysis. The hallmark genes are the high-degree hubs in the bipartite network of viral genes and genomes. The results of network analysis of the entire diversity of double-stranded DNA viruses, which reveals a small number of distinct supermodules, will be presented. Given the ubiquity of parasitic genetic elements, defense systems evolved by the cellular hosts are just as ubiquitous and extremely diverse and elaborate. A central feature in the evolution of antivirus defense is the recurrent recruitment of components of mobile genetic elements (MGE) themselves for defence functions and the converse hijacking of defence systems by parasites for antidefense. Thus, the Virus World and the defence systems effectively form a single, interconnected ‘supernetwork’. The multiple contributions of parasitic elements to the evolution of defence systems, in particular CRISPR-Cas, will be discussed along with the fundamental causes of these complex evolutionary relationships.

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