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Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects

A central question linking ecology with evolutionary biology is how environmental heterogeneity can drive adaptive genetic divergence among populations. We examined adaptive divergence of four stream insects from six adjacent catchments in Japan by combining field measures of habitat and resource co...

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Autores principales: Watanabe, Kozo, Kazama, So, Omura, Tatsuo, Monaghan, Michael T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969376/
https://www.ncbi.nlm.nih.gov/pubmed/24681871
http://dx.doi.org/10.1371/journal.pone.0093055
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author Watanabe, Kozo
Kazama, So
Omura, Tatsuo
Monaghan, Michael T.
author_facet Watanabe, Kozo
Kazama, So
Omura, Tatsuo
Monaghan, Michael T.
author_sort Watanabe, Kozo
collection PubMed
description A central question linking ecology with evolutionary biology is how environmental heterogeneity can drive adaptive genetic divergence among populations. We examined adaptive divergence of four stream insects from six adjacent catchments in Japan by combining field measures of habitat and resource components with genome scans of non-neutral Amplified Fragment Length Polymorphism (AFLP) loci. Neutral genetic variation was used to measure gene flow and non-neutral genetic variation was used to test for adaptive divergence. We identified the environmental characteristics contributing to divergence by comparing genetic distances at non-neutral loci between sites with Euclidean distances for each of 15 environmental variables. Comparisons were made using partial Mantel tests to control for geographic distance. In all four species, we found strong evidence for non-neutral divergence along environmental gradients at between 6 and 21 loci per species. The relative contribution of these environmental variables to each species' ecological niche was quantified as the specialization index, S, based on ecological data. In each species, the variable most significantly correlated with genetic distance at non-neutral loci was the same variable along which each species was most narrowly distributed (i.e., highest S). These were gradients of elevation (two species), chlorophyll-a, and ammonia-nitrogen. This adaptive divergence occurred in the face of ongoing gene flow (F (st) = 0.01–0.04), indicating that selection was strong enough to overcome homogenization at the landscape scale. Our results suggest that adaptive divergence is pronounced, occurs along different environmental gradients for different species, and may consistently occur along the narrowest components of species' niche.
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spelling pubmed-39693762014-04-01 Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects Watanabe, Kozo Kazama, So Omura, Tatsuo Monaghan, Michael T. PLoS One Research Article A central question linking ecology with evolutionary biology is how environmental heterogeneity can drive adaptive genetic divergence among populations. We examined adaptive divergence of four stream insects from six adjacent catchments in Japan by combining field measures of habitat and resource components with genome scans of non-neutral Amplified Fragment Length Polymorphism (AFLP) loci. Neutral genetic variation was used to measure gene flow and non-neutral genetic variation was used to test for adaptive divergence. We identified the environmental characteristics contributing to divergence by comparing genetic distances at non-neutral loci between sites with Euclidean distances for each of 15 environmental variables. Comparisons were made using partial Mantel tests to control for geographic distance. In all four species, we found strong evidence for non-neutral divergence along environmental gradients at between 6 and 21 loci per species. The relative contribution of these environmental variables to each species' ecological niche was quantified as the specialization index, S, based on ecological data. In each species, the variable most significantly correlated with genetic distance at non-neutral loci was the same variable along which each species was most narrowly distributed (i.e., highest S). These were gradients of elevation (two species), chlorophyll-a, and ammonia-nitrogen. This adaptive divergence occurred in the face of ongoing gene flow (F (st) = 0.01–0.04), indicating that selection was strong enough to overcome homogenization at the landscape scale. Our results suggest that adaptive divergence is pronounced, occurs along different environmental gradients for different species, and may consistently occur along the narrowest components of species' niche. Public Library of Science 2014-03-28 /pmc/articles/PMC3969376/ /pubmed/24681871 http://dx.doi.org/10.1371/journal.pone.0093055 Text en © 2014 Watanabe et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Watanabe, Kozo
Kazama, So
Omura, Tatsuo
Monaghan, Michael T.
Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title_full Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title_fullStr Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title_full_unstemmed Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title_short Adaptive Genetic Divergence along Narrow Environmental Gradients in Four Stream Insects
title_sort adaptive genetic divergence along narrow environmental gradients in four stream insects
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969376/
https://www.ncbi.nlm.nih.gov/pubmed/24681871
http://dx.doi.org/10.1371/journal.pone.0093055
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