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Author de Visser, J. Arjan G. M. ♦ Park, Su-Chan ♦ Krug, Joachim
Source arXiv.org
Content type Text
File Format PDF
Date of Submission 2008-07-18
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Natural sciences & mathematics ♦ Physics ♦ Life sciences; biology
Subject Keyword Quantitative Biology - Populations and Evolution ♦ Condensed Matter - Disordered Systems and Neural Networks ♦ physics:cond-mat ♦ q-bio
Abstract The nature of epistasis has important consequences for the evolutionary significance of sex and recombination. Recent efforts to find negative epistasis as source of negative linkage disequilibrium and associated long-term sex advantage have yielded little support. Sign epistasis, where the sign of the fitness effects of alleles varies across genetic backgrounds, is responsible for ruggedness of the fitness landscape with implications for the evolution of sex that have been largely unexplored. Here, we describe fitness landscapes for two sets of strains of the asexual fungus \emph{Aspergillus niger} involving all combinations of five mutations. We find that $\sim 30$% of the single-mutation fitness effects are positive despite their negative effect in the wild-type strain, and that several local fitness maxima and minima are present. We then compare adaptation of sexual and asexual populations on these empirical fitness landscapes using simulations. The results show a general disadvantage of sex on these rugged landscapes, caused by the break down by recombination of genotypes escaping from local peaks. Sex facilitates escape from a local peak only for some parameter values on one landscape, indicating its dependence on the landscape's topography. We discuss possible reasons for the discrepancy between our results and the reports of faster adaptation of sexual populations.
Description Reference: American Naturalist 174 (2009) S15-S30 (with substantial revisions)
Educational Use Research
Learning Resource Type Article


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