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Park, Su-Chan and Krug, Joachim ORCID: 0000-0002-2143-6490 (2013). Rate of Adaptation in Sexuals and Asexuals: A Solvable Model of the Fisher-Muller Effect. Genetics, 195 (3). S. 941 - 958. BETHESDA: GENETICS SOC AM. ISSN 1943-2631

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Abstract

The adaptation of large asexual populations is hampered by the competition between independently arising beneficial mutations in different individuals, which is known as clonal interference. In classic work, Fisher and Muller proposed that recombination provides an evolutionary advantage in large populations by alleviating this competition. Based on recent progress in quantifying the speed of adaptation in asexual populations undergoing clonal interference, we present a detailed analysis of the Fisher-Muller mechanism for a model genome consisting of two loci with an infinite number of beneficial alleles each and multiplicative (nonepistatic) fitness effects. We solve the deterministic, infinite population dynamics exactly and show that, for a particular, natural mutation scheme, the speed of adaptation in sexuals is twice as large as in asexuals. This result is argued to hold for any nonzero value of the rate of recombination. Guided by the infinite population result and by previous work on asexual adaptation, we postulate an expression for the speed of adaptation in finite sexual populations that agrees with numerical simulations over a wide range of population sizes and recombination rates. The ratio of the sexual to asexual adaptation speed is a function of population size that increases in the clonal interference regime and approaches 2 for extremely large populations. The simulations also show that the imbalance between the numbers of accumulated mutations at the two loci is strongly suppressed even by a small amount of recombination. The generalization of the model to an arbitrary number L of loci is briefly discussed. If each offspring samples the alleles at each locus from the gene pool of the whole population rather than from two parents, the ratio of the sexual to asexual adaptation speed is approximately equal to L in large populations. A possible realization of this scenario is the reassortment of genetic material in RNA viruses with L genomic segments.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Park, Su-Chan UNSPECIFIED UNSPECIFIED UNSPECIFIED Krug, Joachim UNSPECIFIED orcid.org/0000-0002-2143-6490 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-472221
DOI:	10.1534/genetics.113.155135
Journal or Publication Title:	Genetics
Volume:	195
Number:	3
Page Range:	S. 941 - 958
Date:	2013
Publisher:	GENETICS SOC AM
Place of Publication:	BETHESDA
ISSN:	1943-2631
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MUTATION-SELECTION BALANCE; BENEFICIAL MUTATIONS; CLONAL INTERFERENCE; ESCHERICHIA-COLI; ADAPTIVE EVOLUTION; RNA VIRUSES; POPULATIONS; SEX; RECOMBINATION; FITNESS Multiple languages Genetics & Heredity Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47222