Universität zu Köln

Schoustra, Sijmen, Hwang, Sungmin, Krug, Joachim ORCID: 0000-0002-2143-6490 and de Visser, J. Arjan G. M. (2016). Diminishing-returns epistasis among random beneficial mutations in a multicellular fungus. Proc. R. Soc. B-Biol. Sci., 283 (1837). LONDON: ROYAL SOC. ISSN 1471-2954

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Abstract

Adaptive evolution ultimately is fuelled by mutations generating novel genetic variation. Non-additivity of fitness effects of mutations (called epistasis) may affect the dynamics and repeatability of adaptation. However, understanding the importance and implications of epistasis is hampered by the observation of substantial variation in patterns of epistasis across empirical studies. Interestingly, some recent studies report increasingly smaller benefits of beneficial mutations once genotypes become better adapted (called diminishing-returns epistasis) in unicellular microbes and single genes. Here, we use Fisher's geometric model (FGM) to generate analytical predictions about the relationship between the effect size of mutations and the extent of epistasis. We then test these predictions using the multicellular fungus Aspergillus nidulans by generating a collection of 108 strains in either a poor or a rich nutrient environment that each carry a beneficial mutation and constructing pairwise combinations using sexual crosses. Our results support the predictions from FGM and indicate negative epistasis among beneficial mutations in both environments, which scale with mutational effect size. Hence, our findings show the importance of diminishing-returns epistasis among beneficial mutations also for a multicellular organism, and suggest that this pattern reflects a generic constraint operating at diverse levels of biological organization.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schoustra, Sijmen UNSPECIFIED UNSPECIFIED UNSPECIFIED Hwang, Sungmin UNSPECIFIED UNSPECIFIED UNSPECIFIED Krug, Joachim UNSPECIFIED orcid.org/0000-0002-2143-6490 UNSPECIFIED de Visser, J. Arjan G. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-266134
DOI:	10.1098/rspb.2016.1376
Journal or Publication Title:	Proc. R. Soc. B-Biol. Sci.
Volume:	283
Number:	1837
Date:	2016
Publisher:	ROYAL SOC
Place of Publication:	LONDON
ISSN:	1471-2954
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institut für Biologische Physik
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EMPIRICAL FITNESS LANDSCAPES; FISHERS GEOMETRIC MODEL; ASPERGILLUS-NIDULANS; PERVASIVE EPISTASIS; NATURAL-SELECTION; ADAPTATION; EVOLUTION; COMPLEXITY; RESISTANCE; GENE Multiple languages Biology; Ecology; Evolutionary Biology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26613