Signals of major histocompatibility complex overdominance in a wild salmonid population
The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but co...
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crroyalsociety:10.1098/rspb.2009.0727 2024-06-02T08:00:06+00:00 Signals of major histocompatibility complex overdominance in a wild salmonid population Kekäläinen, Jukka Vallunen, J. Albert Primmer, Craig R. Rättyä, Jouni Taskinen, Jouni 2009 http://dx.doi.org/10.1098/rspb.2009.0727 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2009.0727 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2009.0727 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society B: Biological Sciences volume 276, issue 1670, page 3133-3140 ISSN 0962-8452 1471-2954 journal-article 2009 crroyalsociety https://doi.org/10.1098/rspb.2009.0727 2024-05-07T14:16:45Z The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but convincing evidence for overdominant selection in natural populations has been lacking. We present strong evidence consistent with MHC-specific overdominance in a free-living population of Arctic charr ( Salvelinus alpinus ) in northernmost Europe. In this population, where just two MHC alleles were observed, MHC heterozygous fish had a lower parasite load, were in better condition (as estimated by a fatness indicator) and had higher survival under stress than either of the homozygotes. Conversely, there was no consistent association between these fitness measures and assumedly neutral microsatellite variability, indicating an MHC-specific effect. Our results provide convincing empirical evidence consistent with the notion that overdominance can be an important evolutionary mechanism contributing to MHC polymorphism in wild animal populations. They also support a recent simulation study indicating that the number of alleles expected to be maintained at an MHC loci can be low, even under strong heterozygote advantage. Article in Journal/Newspaper Arctic charr Arctic Salvelinus alpinus The Royal Society Arctic Proceedings of the Royal Society B: Biological Sciences 276 1670 3133 3140 |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but convincing evidence for overdominant selection in natural populations has been lacking. We present strong evidence consistent with MHC-specific overdominance in a free-living population of Arctic charr ( Salvelinus alpinus ) in northernmost Europe. In this population, where just two MHC alleles were observed, MHC heterozygous fish had a lower parasite load, were in better condition (as estimated by a fatness indicator) and had higher survival under stress than either of the homozygotes. Conversely, there was no consistent association between these fitness measures and assumedly neutral microsatellite variability, indicating an MHC-specific effect. Our results provide convincing empirical evidence consistent with the notion that overdominance can be an important evolutionary mechanism contributing to MHC polymorphism in wild animal populations. They also support a recent simulation study indicating that the number of alleles expected to be maintained at an MHC loci can be low, even under strong heterozygote advantage. |
format |
Article in Journal/Newspaper |
author |
Kekäläinen, Jukka Vallunen, J. Albert Primmer, Craig R. Rättyä, Jouni Taskinen, Jouni |
spellingShingle |
Kekäläinen, Jukka Vallunen, J. Albert Primmer, Craig R. Rättyä, Jouni Taskinen, Jouni Signals of major histocompatibility complex overdominance in a wild salmonid population |
author_facet |
Kekäläinen, Jukka Vallunen, J. Albert Primmer, Craig R. Rättyä, Jouni Taskinen, Jouni |
author_sort |
Kekäläinen, Jukka |
title |
Signals of major histocompatibility complex overdominance in a wild salmonid population |
title_short |
Signals of major histocompatibility complex overdominance in a wild salmonid population |
title_full |
Signals of major histocompatibility complex overdominance in a wild salmonid population |
title_fullStr |
Signals of major histocompatibility complex overdominance in a wild salmonid population |
title_full_unstemmed |
Signals of major histocompatibility complex overdominance in a wild salmonid population |
title_sort |
signals of major histocompatibility complex overdominance in a wild salmonid population |
publisher |
The Royal Society |
publishDate |
2009 |
url |
http://dx.doi.org/10.1098/rspb.2009.0727 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2009.0727 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2009.0727 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic charr Arctic Salvelinus alpinus |
genre_facet |
Arctic charr Arctic Salvelinus alpinus |
op_source |
Proceedings of the Royal Society B: Biological Sciences volume 276, issue 1670, page 3133-3140 ISSN 0962-8452 1471-2954 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspb.2009.0727 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
276 |
container_issue |
1670 |
container_start_page |
3133 |
op_container_end_page |
3140 |
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1800744113543315456 |