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Iván Andreu defends his thesis on collective evolution in viruses

  • April 29th, 2022
Iván Andreu, Rafael Sanjuán
Iván Andreu, Rafael Sanjuán

This doctoral thesis, supervised by Rafael Sanjuán Verdeguer, addresses the evolutionary implications of the formation of collective infectious units in viral pathogens. The results have been published in the journals Current Biology, mBio and Science Advances. The thesis was defended on April 29, 2022.

Viruses employ a variety of strategies to transmit multiple viral particles or genomes into a single cell. These collective transmission strategies promote sustained interaction between co-infecting viruses, which enables the evolution of social interactions such as cooperation, but also conflict. Moreover, in the absence of other sources of benefits, the association of multiple virions or viral genomes to form collective infectious units implies a dispersive cost by limiting the total capacity of viruses to initiate new foci of infection. The thesis, entitled «Evolutionary implications of collective virus transmission», analyzes whether collective transmission provides benefits derived from co-infection that compensate its dispersive cost in the short term, but also whether it promotes the evolution of cooperation or conflict in the longer term. To this end, the cooperative dynamics of coinfection are studied by combining mathematical modeling with experiments. In addition, using vesicular stomatitis virus viral aggregates, the net and immediate impact of this collective mode of transmission on viral biological efficacy has been experimentally determined, discerning the main factors and mechanisms involved. Likewise, the non-immediate consequences of aggregation on the evolution of social interactions and viral diversity have been explored.

Iván Andreu's thesis has been carried out in the Virus Experimental Evolution research group at I2SysBio, and has been directed by Rafael Sanjuán (Tenured Professor at the Department of Genetics, Universitat de València and Principal Investigator of the group). During the development of the thesis Iván Andreu has enjoyed a contract within the University Teacher Training Program (FPU, Ministry of Universities). The examining board was formed by José Manuel Cuevas (Tenured Professor at the Department of Genetics, UV and I2SysBio researcher), Ester Lázaro (Research Scientist of CSIC, Center of Astrobiology CSIC-INTA) and Santiago F. Elena (Research Professor of CSIC, I2SysBio), who have qualified the thesis as outstanding.