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Brain differences in ecologically differentiated sticklebacks

Populations that have recently diverged offer a powerful model for studying evolution. Ecological differences are expected to generate divergent selection on multiple traits, including neurobiological ones. Animals must detect, process, and act on information from their surroundings and the form of...

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Autores principales: Keagy, Jason, Braithwaite, Victoria A, Boughman, Janette W
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5905471/
https://www.ncbi.nlm.nih.gov/pubmed/30402065
http://dx.doi.org/10.1093/cz/zox074
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author Keagy, Jason
Braithwaite, Victoria A
Boughman, Janette W
author_facet Keagy, Jason
Braithwaite, Victoria A
Boughman, Janette W
author_sort Keagy, Jason
collection PubMed
description Populations that have recently diverged offer a powerful model for studying evolution. Ecological differences are expected to generate divergent selection on multiple traits, including neurobiological ones. Animals must detect, process, and act on information from their surroundings and the form of this information can be highly dependent on the environment. We might expect different environments to generate divergent selection not only on the sensory organs, but also on the brain regions responsible for processing sensory information. Here, we test this hypothesis using recently evolved reproductively isolated species pairs of threespine stickleback fish Gasterosteus aculeatus that have well-described differences in many morphological and behavioral traits correlating with ecological differences. We use a state-of-the-art method, magnetic resonance imaging, to get accurate volumetric data for 2 sensory processing regions, the olfactory bulbs and optic tecta. We found a tight correlation between ecology and the size of these brain regions relative to total brain size in 2 lakes with intact species pairs. Limnetic fish, which rely heavily on vision, had relatively larger optic tecta and smaller olfactory bulbs compared with benthic fish, which utilize olfaction to a greater extent. Benthic fish also had larger total brain volumes relative to their body size compared with limnetic fish. These differences were erased in a collapsed species pair in Enos Lake where anthropogenic disturbance has led to intense hybridization. Together these data indicate that evolution of sensory processing regions can occur rapidly and independently.
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spelling pubmed-59054712018-11-06 Brain differences in ecologically differentiated sticklebacks Keagy, Jason Braithwaite, Victoria A Boughman, Janette W Curr Zool Special Column: Ecology and Evolution along Environmental Gradients Populations that have recently diverged offer a powerful model for studying evolution. Ecological differences are expected to generate divergent selection on multiple traits, including neurobiological ones. Animals must detect, process, and act on information from their surroundings and the form of this information can be highly dependent on the environment. We might expect different environments to generate divergent selection not only on the sensory organs, but also on the brain regions responsible for processing sensory information. Here, we test this hypothesis using recently evolved reproductively isolated species pairs of threespine stickleback fish Gasterosteus aculeatus that have well-described differences in many morphological and behavioral traits correlating with ecological differences. We use a state-of-the-art method, magnetic resonance imaging, to get accurate volumetric data for 2 sensory processing regions, the olfactory bulbs and optic tecta. We found a tight correlation between ecology and the size of these brain regions relative to total brain size in 2 lakes with intact species pairs. Limnetic fish, which rely heavily on vision, had relatively larger optic tecta and smaller olfactory bulbs compared with benthic fish, which utilize olfaction to a greater extent. Benthic fish also had larger total brain volumes relative to their body size compared with limnetic fish. These differences were erased in a collapsed species pair in Enos Lake where anthropogenic disturbance has led to intense hybridization. Together these data indicate that evolution of sensory processing regions can occur rapidly and independently. Oxford University Press 2018-04 2017-11-30 /pmc/articles/PMC5905471/ /pubmed/30402065 http://dx.doi.org/10.1093/cz/zox074 Text en © The Author(s) (2017). Published by Oxford University Press. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Special Column: Ecology and Evolution along Environmental Gradients
Keagy, Jason
Braithwaite, Victoria A
Boughman, Janette W
Brain differences in ecologically differentiated sticklebacks
title Brain differences in ecologically differentiated sticklebacks
title_full Brain differences in ecologically differentiated sticklebacks
title_fullStr Brain differences in ecologically differentiated sticklebacks
title_full_unstemmed Brain differences in ecologically differentiated sticklebacks
title_short Brain differences in ecologically differentiated sticklebacks
title_sort brain differences in ecologically differentiated sticklebacks
topic Special Column: Ecology and Evolution along Environmental Gradients
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5905471/
https://www.ncbi.nlm.nih.gov/pubmed/30402065
http://dx.doi.org/10.1093/cz/zox074
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