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The impact of high‐order epistasis in the within‐host fitness of a positive‐sense plant RNA virus
Author(s) -
Lalić J.,
Elena S. F.
Publication year - 2015
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12748
Subject(s) - epistasis , biology , fitness landscape , adaptation (eye) , genetics , host (biology) , evolutionary biology , rna virus , tobacco etch virus , genetic fitness , population , coevolution , arabidopsis , experimental evolution , neutral network , mutation rate , recombination , local adaptation , mutation , potyvirus , plant virus , rna , virus , gene , demography , neuroscience , sociology , machine learning , mutant , artificial neural network , computer science
RNA viruses are the main source of emerging infectious diseases because of the evolutionary potential bestowed by their fast replication, large population sizes and high mutation and recombination rates. However, an equally important property, which is usually neglected, is the topography of the fitness landscape. How many fitness maxima exist and how well they are connected is especially interesting, as this determines the number of accessible evolutionary pathways. To address this question, we have reconstructed a region of the fitness landscape of tobacco etch potyvirus constituted by mutations observed during the experimental adaptation of the virus to the novel host Arabidopsis thaliana . Fitness was measured for many genotypes and showed the existence of multiple peaks and holes in the landscape. We found prevailing epistatic effects between mutations, with cases of reciprocal sign epistasis being common among pairs of mutations. We also found that high‐order epistasis was as important as pairwise epistasis in their contribution to fitness. Therefore, results suggest that the landscape was rugged due to the existence of holes caused by lethal genotypes, that a very limited number of potential neutral paths exist and that it contained a single adaptive peak.