title: Selection for robustness in mutagenized RNA viruses.
abstract: Mutational robustness is defined as the constancy of a phenotype in the face of deleterious mutations. Whether robustness can be directly favored by natural selection remains controversial. Theory and in silico experiments predict that, at high mutation rates, slow-replicating genotypes can potentially outcompete faster counterparts if they benefit from a higher robustness. Here, we experimentally validate this hypothesis, dubbed the "survival of the flattest," using two populations of the vesicular stomatitis RNA virus. Characterization of fitness distributions and genetic variability indicated that one population showed a higher replication rate, whereas the other was more robust to mutation. The faster replicator outgrew its robust counterpart in standard competition assays, but the outcome was reversed in the presence of chemical mutagens. These results show that selection can directly favor mutational robustness and reveal a novel viral resistance mechanism against treatment by lethal mutagenesis.
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, València, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Sanjuán
authors.forename: José M
authors.initials: JM
authors.lastname: Cuevas
authors.forename: Victoria
authors.initials: V
authors.lastname: Furió
authors.forename: Edward C
authors.initials: EC
authors.lastname: Holmes
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D012641:Selection, Genetic; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication / Q000235:genetics*