The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression
Ecological factors have a major role shaping natural variation in body-size, although the underlying mechanisms are poorly understood. Icelandic Arctic charr (Salvelinus alpinus L.) populations represent an ideal model to understand body-size evolution, since adult-dwarfism has arisen independently...
Published in: | Molecular Ecology |
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2011
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Online Access: | https://research-portal.st-andrews.ac.uk/en/researchoutput/the-parallel-evolution-of-dwarfism-in-arctic-charr-is-accompanied-by-adaptive-divergence-in-mtorpathway-gene-expression(7e879129-f873-4603-bbd2-2ebfd38bcf59).html https://doi.org/10.1111/j.1365-294X.2011.05172.x |
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/7e879129-f873-4603-bbd2-2ebfd38bcf59 2024-06-23T07:48:25+00:00 The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression MacQueen, Daniel John Kristjánsson, Bjarni K. Paxton, Charles G. M. Vieira-Johnston, Vera Lucia Almeida Johnston, Ian Alistair 2011 https://research-portal.st-andrews.ac.uk/en/researchoutput/the-parallel-evolution-of-dwarfism-in-arctic-charr-is-accompanied-by-adaptive-divergence-in-mtorpathway-gene-expression(7e879129-f873-4603-bbd2-2ebfd38bcf59).html https://doi.org/10.1111/j.1365-294X.2011.05172.x eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/the-parallel-evolution-of-dwarfism-in-arctic-charr-is-accompanied-by-adaptive-divergence-in-mtorpathway-gene-expression(7e879129-f873-4603-bbd2-2ebfd38bcf59).html info:eu-repo/semantics/restrictedAccess MacQueen , D J , Kristjánsson , B K , Paxton , C G M , Vieira-Johnston , V L A & Johnston , I A 2011 , ' The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression ' , Molecular Ecology , vol. 20 , no. 15 , pp. 3167-3184 . https://doi.org/10.1111/j.1365-294X.2011.05172.x article 2011 ftunstandrewcris https://doi.org/10.1111/j.1365-294X.2011.05172.x 2024-06-13T00:31:31Z Ecological factors have a major role shaping natural variation in body-size, although the underlying mechanisms are poorly understood. Icelandic Arctic charr (Salvelinus alpinus L.) populations represent an ideal model to understand body-size evolution, since adult-dwarfism has arisen independently on multiple occasions in response to parallel environmental pressures. The mechanistic target of rapamycin (mTOR)-pathway transmits signals from the environment to control cellular-growth and is a primary candidate to be under selection for the dwarf phenotype. To test this hypothesis, we modified ‘inputs’ to this pathway in 5 dwarf and 2 generalist populations (with ancestral life-history and body-size traits), using a standardised manipulation of food-intake in a common environment. The skeletal-muscle transcript levels of 21 mTOR-pathway genes were quantified in 274 individuals (ca. 6000 datapoints) and statistical modelling used to elucidate sources of variation. Constitutive expression differences between-populations were the main component of variation for around three-quarters of the studied genes, irrespective of nutritional-state and body-size phenotype. There was evidence for stabilizing-selection acting among-populations, conserving the nutritionally-dependent regulation of pathway genes controlling muscle-atrophy. There were 3 genes (mTOR, 4E-BP-1 and IGFBP4), where the expression-variation between dwarf and generalist populations exceeded the between-population variation. Divergence in expression of these candidate adaptive genes was most evident during a period of rapid growth following sustained-fasting and was directionally consistent with their functions regulating growth and protein-synthesis. We concluded that selection has operated efficiently to shape gene expression evolution in Icelandic charr populations and that the regulation of certain mTOR-pathway genes evolved adaptively in locations favouring dwarfism, resulting in reduced muscle protein-accretion under growth-favouring conditions. Article in Journal/Newspaper Arctic Arctic charr Arctic Salvelinus alpinus University of St Andrews: Research Portal Arctic Molecular Ecology 20 15 3167 3184 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
description |
Ecological factors have a major role shaping natural variation in body-size, although the underlying mechanisms are poorly understood. Icelandic Arctic charr (Salvelinus alpinus L.) populations represent an ideal model to understand body-size evolution, since adult-dwarfism has arisen independently on multiple occasions in response to parallel environmental pressures. The mechanistic target of rapamycin (mTOR)-pathway transmits signals from the environment to control cellular-growth and is a primary candidate to be under selection for the dwarf phenotype. To test this hypothesis, we modified ‘inputs’ to this pathway in 5 dwarf and 2 generalist populations (with ancestral life-history and body-size traits), using a standardised manipulation of food-intake in a common environment. The skeletal-muscle transcript levels of 21 mTOR-pathway genes were quantified in 274 individuals (ca. 6000 datapoints) and statistical modelling used to elucidate sources of variation. Constitutive expression differences between-populations were the main component of variation for around three-quarters of the studied genes, irrespective of nutritional-state and body-size phenotype. There was evidence for stabilizing-selection acting among-populations, conserving the nutritionally-dependent regulation of pathway genes controlling muscle-atrophy. There were 3 genes (mTOR, 4E-BP-1 and IGFBP4), where the expression-variation between dwarf and generalist populations exceeded the between-population variation. Divergence in expression of these candidate adaptive genes was most evident during a period of rapid growth following sustained-fasting and was directionally consistent with their functions regulating growth and protein-synthesis. We concluded that selection has operated efficiently to shape gene expression evolution in Icelandic charr populations and that the regulation of certain mTOR-pathway genes evolved adaptively in locations favouring dwarfism, resulting in reduced muscle protein-accretion under growth-favouring conditions. |
format |
Article in Journal/Newspaper |
author |
MacQueen, Daniel John Kristjánsson, Bjarni K. Paxton, Charles G. M. Vieira-Johnston, Vera Lucia Almeida Johnston, Ian Alistair |
spellingShingle |
MacQueen, Daniel John Kristjánsson, Bjarni K. Paxton, Charles G. M. Vieira-Johnston, Vera Lucia Almeida Johnston, Ian Alistair The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
author_facet |
MacQueen, Daniel John Kristjánsson, Bjarni K. Paxton, Charles G. M. Vieira-Johnston, Vera Lucia Almeida Johnston, Ian Alistair |
author_sort |
MacQueen, Daniel John |
title |
The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
title_short |
The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
title_full |
The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
title_fullStr |
The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
title_full_unstemmed |
The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression |
title_sort |
parallel evolution of dwarfism in arctic charr is accompanied by adaptive divergence in mtor-pathway gene expression |
publishDate |
2011 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/the-parallel-evolution-of-dwarfism-in-arctic-charr-is-accompanied-by-adaptive-divergence-in-mtorpathway-gene-expression(7e879129-f873-4603-bbd2-2ebfd38bcf59).html https://doi.org/10.1111/j.1365-294X.2011.05172.x |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctic charr Arctic Salvelinus alpinus |
genre_facet |
Arctic Arctic charr Arctic Salvelinus alpinus |
op_source |
MacQueen , D J , Kristjánsson , B K , Paxton , C G M , Vieira-Johnston , V L A & Johnston , I A 2011 , ' The parallel evolution of dwarfism in Arctic charr is accompanied by adaptive divergence in mTOR-pathway gene expression ' , Molecular Ecology , vol. 20 , no. 15 , pp. 3167-3184 . https://doi.org/10.1111/j.1365-294X.2011.05172.x |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/the-parallel-evolution-of-dwarfism-in-arctic-charr-is-accompanied-by-adaptive-divergence-in-mtorpathway-gene-expression(7e879129-f873-4603-bbd2-2ebfd38bcf59).html |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1111/j.1365-294X.2011.05172.x |
container_title |
Molecular Ecology |
container_volume |
20 |
container_issue |
15 |
container_start_page |
3167 |
op_container_end_page |
3184 |
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1802638835857752064 |