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Sympatric ecological divergence with coevolution of niche preference

Reinforcement, the increase of assortative mating driven by selection against unfit hybrids, is conditional on pre-existing divergence. Yet, for ecological divergence to precede the evolution of assortment, strict symmetries between fitnesses in niches must hold, and/or there must be low gene flow b...

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Autores principales: Payne, Pavel, Polechová, Jitka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423286/
https://www.ncbi.nlm.nih.gov/pubmed/32654636
http://dx.doi.org/10.1098/rstb.2019.0749
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author Payne, Pavel
Polechová, Jitka
author_facet Payne, Pavel
Polechová, Jitka
author_sort Payne, Pavel
collection PubMed
description Reinforcement, the increase of assortative mating driven by selection against unfit hybrids, is conditional on pre-existing divergence. Yet, for ecological divergence to precede the evolution of assortment, strict symmetries between fitnesses in niches must hold, and/or there must be low gene flow between the nascent species. It has thus been argued that conditions favouring sympatric speciation are rarely met in nature. Indeed, we show that under disruptive selection, violating symmetries in niche sizes and increasing strength of the trade-off in selection between the niches quickly leads to loss of genetic variation, instead of evolution of specialists. The region of the parameter space where polymorphism is maintained further narrows with increasing number of loci encoding the diverging trait and the rate of recombination between them. Yet, evolvable assortment and pre-existing assortment both substantially broaden the parameter space within which polymorphism is maintained. Notably, pre-existing niche preference speeds up further increase of assortment, thus facilitating reinforcement in the later phases of speciation. We conclude that in order for sympatric ecological divergence to occur, niche preference must coevolve throughout the divergence process. Even if populations come into secondary contact, having diverged in isolation, niche preference substantially broadens the conditions for coexistence in sympatry and completion of the speciation process. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
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spelling pubmed-74232862020-08-23 Sympatric ecological divergence with coevolution of niche preference Payne, Pavel Polechová, Jitka Philos Trans R Soc Lond B Biol Sci Articles Reinforcement, the increase of assortative mating driven by selection against unfit hybrids, is conditional on pre-existing divergence. Yet, for ecological divergence to precede the evolution of assortment, strict symmetries between fitnesses in niches must hold, and/or there must be low gene flow between the nascent species. It has thus been argued that conditions favouring sympatric speciation are rarely met in nature. Indeed, we show that under disruptive selection, violating symmetries in niche sizes and increasing strength of the trade-off in selection between the niches quickly leads to loss of genetic variation, instead of evolution of specialists. The region of the parameter space where polymorphism is maintained further narrows with increasing number of loci encoding the diverging trait and the rate of recombination between them. Yet, evolvable assortment and pre-existing assortment both substantially broaden the parameter space within which polymorphism is maintained. Notably, pre-existing niche preference speeds up further increase of assortment, thus facilitating reinforcement in the later phases of speciation. We conclude that in order for sympatric ecological divergence to occur, niche preference must coevolve throughout the divergence process. Even if populations come into secondary contact, having diverged in isolation, niche preference substantially broadens the conditions for coexistence in sympatry and completion of the speciation process. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'. The Royal Society 2020-08-31 2020-07-13 /pmc/articles/PMC7423286/ /pubmed/32654636 http://dx.doi.org/10.1098/rstb.2019.0749 Text en © 2020 The Authors. http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/http://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/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Articles
Payne, Pavel
Polechová, Jitka
Sympatric ecological divergence with coevolution of niche preference
title Sympatric ecological divergence with coevolution of niche preference
title_full Sympatric ecological divergence with coevolution of niche preference
title_fullStr Sympatric ecological divergence with coevolution of niche preference
title_full_unstemmed Sympatric ecological divergence with coevolution of niche preference
title_short Sympatric ecological divergence with coevolution of niche preference
title_sort sympatric ecological divergence with coevolution of niche preference
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423286/
https://www.ncbi.nlm.nih.gov/pubmed/32654636
http://dx.doi.org/10.1098/rstb.2019.0749
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