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The costs and benefits of dispersal in small populations

Dispersal has three major effects on adaptation. First, gene flow mixes alleles adapted to different environments, potentially hindering (swamping) adaptation. Second, it brings in other variants and inflates genetic variance: this aids adaptation to spatially (and temporally) varying environments b...

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Detalles Bibliográficos
Autor principal: Polechová, Jitka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8859518/
https://www.ncbi.nlm.nih.gov/pubmed/35184593
http://dx.doi.org/10.1098/rstb.2021.0011
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author Polechová, Jitka
author_facet Polechová, Jitka
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description Dispersal has three major effects on adaptation. First, gene flow mixes alleles adapted to different environments, potentially hindering (swamping) adaptation. Second, it brings in other variants and inflates genetic variance: this aids adaptation to spatially (and temporally) varying environments but if selection is hard, it lowers the mean fitness of the population. Third, neighbourhood size, which determines how weak genetic drift is, increases with dispersal—when genetic drift is strong, increase of the neighbourhood size with dispersal aids adaptation. In this note, I focus on the role of dispersal in environments that change gradually across space, and when local populations are quite small such that genetic drift has a significant effect. Using individual-based simulations, I show that in small populations, even leptokurtic dispersal benefits adaptation by reducing the power of genetic drift. This has implications for management of fragmented or marginal populations: the beneficial effect of increased dispersal into small populations is stronger than swamping of adaption under a broad range of conditions, including a mixture of local and long-distance dispersal. However, when environmental gradient is steep, heavily fat-tailed dispersal will swamp continuous adaptation so that only patches of locally adapted subpopulations remain. This article is part of the theme issue ‘Species’ ranges in the face of changing environments (Part II)’.
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spelling pubmed-88595182022-03-07 The costs and benefits of dispersal in small populations Polechová, Jitka Philos Trans R Soc Lond B Biol Sci Articles Dispersal has three major effects on adaptation. First, gene flow mixes alleles adapted to different environments, potentially hindering (swamping) adaptation. Second, it brings in other variants and inflates genetic variance: this aids adaptation to spatially (and temporally) varying environments but if selection is hard, it lowers the mean fitness of the population. Third, neighbourhood size, which determines how weak genetic drift is, increases with dispersal—when genetic drift is strong, increase of the neighbourhood size with dispersal aids adaptation. In this note, I focus on the role of dispersal in environments that change gradually across space, and when local populations are quite small such that genetic drift has a significant effect. Using individual-based simulations, I show that in small populations, even leptokurtic dispersal benefits adaptation by reducing the power of genetic drift. This has implications for management of fragmented or marginal populations: the beneficial effect of increased dispersal into small populations is stronger than swamping of adaption under a broad range of conditions, including a mixture of local and long-distance dispersal. However, when environmental gradient is steep, heavily fat-tailed dispersal will swamp continuous adaptation so that only patches of locally adapted subpopulations remain. This article is part of the theme issue ‘Species’ ranges in the face of changing environments (Part II)’. The Royal Society 2022-04-11 2022-02-21 /pmc/articles/PMC8859518/ /pubmed/35184593 http://dx.doi.org/10.1098/rstb.2021.0011 Text en © 2022 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Articles
Polechová, Jitka
The costs and benefits of dispersal in small populations
title The costs and benefits of dispersal in small populations
title_full The costs and benefits of dispersal in small populations
title_fullStr The costs and benefits of dispersal in small populations
title_full_unstemmed The costs and benefits of dispersal in small populations
title_short The costs and benefits of dispersal in small populations
title_sort costs and benefits of dispersal in small populations
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8859518/
https://www.ncbi.nlm.nih.gov/pubmed/35184593
http://dx.doi.org/10.1098/rstb.2021.0011
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