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Hybrid fitness effects modify fixation probabilities of introgressed alleles
Hybridization is a common occurrence in natural populations, and introgression is a major source of genetic variation. Despite the evolutionary importance of adaptive introgression, classical population genetics theory does not take into account hybrid fitness effects. Specifically, heterosis (i.e....
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9258535/ https://www.ncbi.nlm.nih.gov/pubmed/35536195 http://dx.doi.org/10.1093/g3journal/jkac113 |
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author | Pfennig, Aaron Lachance, Joseph |
author_facet | Pfennig, Aaron Lachance, Joseph |
author_sort | Pfennig, Aaron |
collection | PubMed |
description | Hybridization is a common occurrence in natural populations, and introgression is a major source of genetic variation. Despite the evolutionary importance of adaptive introgression, classical population genetics theory does not take into account hybrid fitness effects. Specifically, heterosis (i.e. hybrid vigor) and Dobzhansky–Muller incompatibilities influence the fates of introgressed alleles. Here, we explicitly account for polygenic, unlinked hybrid fitness effects when tracking a rare introgressed marker allele. These hybrid fitness effects quickly decay over time due to repeated backcrossing, enabling a separation-of-timescales approach. Using diffusion and branching process theory in combination with computer simulations, we formalize the intuition behind how hybrid fitness effects affect introgressed alleles. We find that hybrid fitness effects can significantly hinder or boost the fixation probability of introgressed alleles, depending on the relative strength of heterosis and Dobzhansky–Muller incompatibilities effects. We show that the inclusion of a correction factor (α, representing the compounded effects of hybrid fitness effects over time) into classic population genetics theory yields accurate fixation probabilities. Despite having a strong impact on the probability of fixation, hybrid fitness effects only subtly change the distribution of fitness effects of introgressed alleles that reach fixation. Although strong Dobzhansky–Muller incompatibility effects may expedite the loss of introgressed alleles, fixation times are largely unchanged by hybrid fitness effects. |
format | Online Article Text |
id | pubmed-9258535 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-92585352022-07-07 Hybrid fitness effects modify fixation probabilities of introgressed alleles Pfennig, Aaron Lachance, Joseph G3 (Bethesda) Investigation Hybridization is a common occurrence in natural populations, and introgression is a major source of genetic variation. Despite the evolutionary importance of adaptive introgression, classical population genetics theory does not take into account hybrid fitness effects. Specifically, heterosis (i.e. hybrid vigor) and Dobzhansky–Muller incompatibilities influence the fates of introgressed alleles. Here, we explicitly account for polygenic, unlinked hybrid fitness effects when tracking a rare introgressed marker allele. These hybrid fitness effects quickly decay over time due to repeated backcrossing, enabling a separation-of-timescales approach. Using diffusion and branching process theory in combination with computer simulations, we formalize the intuition behind how hybrid fitness effects affect introgressed alleles. We find that hybrid fitness effects can significantly hinder or boost the fixation probability of introgressed alleles, depending on the relative strength of heterosis and Dobzhansky–Muller incompatibilities effects. We show that the inclusion of a correction factor (α, representing the compounded effects of hybrid fitness effects over time) into classic population genetics theory yields accurate fixation probabilities. Despite having a strong impact on the probability of fixation, hybrid fitness effects only subtly change the distribution of fitness effects of introgressed alleles that reach fixation. Although strong Dobzhansky–Muller incompatibility effects may expedite the loss of introgressed alleles, fixation times are largely unchanged by hybrid fitness effects. Oxford University Press 2022-05-10 /pmc/articles/PMC9258535/ /pubmed/35536195 http://dx.doi.org/10.1093/g3journal/jkac113 Text en © The Author(s) 2022. Published by Oxford University Press on behalf of Genetics Society of America. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Investigation Pfennig, Aaron Lachance, Joseph Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title | Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title_full | Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title_fullStr | Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title_full_unstemmed | Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title_short | Hybrid fitness effects modify fixation probabilities of introgressed alleles |
title_sort | hybrid fitness effects modify fixation probabilities of introgressed alleles |
topic | Investigation |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9258535/ https://www.ncbi.nlm.nih.gov/pubmed/35536195 http://dx.doi.org/10.1093/g3journal/jkac113 |
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