Interfering waves of adaptation promote spatial mixing
Martens, Erik A. LU
and Hallatschek, Oskar
(2011)
In Genetics
189(3).
p.1045-1060
- Abstract
A fundamental problem of asexual adaptation is that beneficial substitutions are not efficiently accumulated in large populations: Beneficial mutations often go extinct because they compete with one another in going to fixation. It has been argued that such clonal interference may have led to the evolution of sex and recombination in well-mixed populations. Here, we study clonal interference, and mechanisms of its mitigation, in an evolutionary model of spatially structured populations with uniform selection pressure. Clonal interference is much more prevalent with spatial structure than without, due to the slow wave-like spread of beneficial mutations through space. We find that the adaptation speed of asexuals saturates when the... (More)
A fundamental problem of asexual adaptation is that beneficial substitutions are not efficiently accumulated in large populations: Beneficial mutations often go extinct because they compete with one another in going to fixation. It has been argued that such clonal interference may have led to the evolution of sex and recombination in well-mixed populations. Here, we study clonal interference, and mechanisms of its mitigation, in an evolutionary model of spatially structured populations with uniform selection pressure. Clonal interference is much more prevalent with spatial structure than without, due to the slow wave-like spread of beneficial mutations through space. We find that the adaptation speed of asexuals saturates when the linear habitat size exceeds a characteristic interference length, which becomes shorter with smaller migration and larger mutation rate. The limiting speed is proportional to μ1/2 and μ1/3 in linear and planar habitats, respectively, where the mutational supply μ is the product of mutation rate and local population density. This scaling and the existence of a speed limit should be amenable to experimental tests as they fall far below predicted adaptation speeds for well-mixed populations (that scale as the logarithm of population size). Finally, we show that not only recombination, but also long-range migration is a highly efficient mechanism of relaxing clonal competition in structured populations. Our conservative estimates of the interference length predict prevalent clonal interference in microbial colonies and biofilms, so clonal competition should be a strong driver of both genetic and spatial mixing in those contexts.
(Less)
- author
- Martens, Erik A.
LU
and Hallatschek, Oskar
- publishing date
- 2011-11-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Genetics
- volume
- 189
- issue
- 3
- pages
- 16 pages
- publisher
- Genetics Society of America
- external identifiers
-
- scopus:81255175660
- pmid:21900264
- ISSN
- 0016-6731
- DOI
- 10.1534/genetics.111.130112
- language
- English
- LU publication?
- no
- additional info
- Copyright: Copyright 2013 Elsevier B.V., All rights reserved.
- id
- 5ee15154-96ec-4a5f-ab6d-432daccc88e2
- date added to LUP
- 2021-03-19 21:29:35
- date last changed
- 2024-07-13 11:38:37
@article{5ee15154-96ec-4a5f-ab6d-432daccc88e2,
abstract = {{<p>A fundamental problem of asexual adaptation is that beneficial substitutions are not efficiently accumulated in large populations: Beneficial mutations often go extinct because they compete with one another in going to fixation. It has been argued that such clonal interference may have led to the evolution of sex and recombination in well-mixed populations. Here, we study clonal interference, and mechanisms of its mitigation, in an evolutionary model of spatially structured populations with uniform selection pressure. Clonal interference is much more prevalent with spatial structure than without, due to the slow wave-like spread of beneficial mutations through space. We find that the adaptation speed of asexuals saturates when the linear habitat size exceeds a characteristic interference length, which becomes shorter with smaller migration and larger mutation rate. The limiting speed is proportional to μ<sup>1/2</sup> and μ<sup>1/3</sup> in linear and planar habitats, respectively, where the mutational supply μ is the product of mutation rate and local population density. This scaling and the existence of a speed limit should be amenable to experimental tests as they fall far below predicted adaptation speeds for well-mixed populations (that scale as the logarithm of population size). Finally, we show that not only recombination, but also long-range migration is a highly efficient mechanism of relaxing clonal competition in structured populations. Our conservative estimates of the interference length predict prevalent clonal interference in microbial colonies and biofilms, so clonal competition should be a strong driver of both genetic and spatial mixing in those contexts.</p>}},
author = {{Martens, Erik A. and Hallatschek, Oskar}},
issn = {{0016-6731}},
language = {{eng}},
month = {{11}},
number = {{3}},
pages = {{1045--1060}},
publisher = {{Genetics Society of America}},
series = {{Genetics}},
title = {{Interfering waves of adaptation promote spatial mixing}},
url = {{http://dx.doi.org/10.1534/genetics.111.130112}},
doi = {{10.1534/genetics.111.130112}},
volume = {{189}},
year = {{2011}},
}