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Changes in variation at the MHC class II DQA locus during the final demise of the woolly mammoth

Pečnerová, Patrícia LU orcid ; Díez-Del-Molino, David ; Vartanyan, Sergey and Dalén, Love LU (2016) In Scientific Reports 6.
Abstract

According to the nearly-neutral theory of evolution, the relative strengths of selection and drift shift in favour of drift at small population sizes. Numerous studies have analysed the effect of bottlenecks and small population sizes on genetic diversity in the MHC, which plays a central role in pathogen recognition and immune defense and is thus considered a model example for the study of adaptive evolution. However, to understand changes in genetic diversity at loci under selection, it is necessary to compare the genetic diversity of a population before and after the bottleneck. In this study, we analyse three fragments of the MHC DQA gene in woolly mammoth samples radiocarbon dated to before and after a well-documented bottleneck... (More)

According to the nearly-neutral theory of evolution, the relative strengths of selection and drift shift in favour of drift at small population sizes. Numerous studies have analysed the effect of bottlenecks and small population sizes on genetic diversity in the MHC, which plays a central role in pathogen recognition and immune defense and is thus considered a model example for the study of adaptive evolution. However, to understand changes in genetic diversity at loci under selection, it is necessary to compare the genetic diversity of a population before and after the bottleneck. In this study, we analyse three fragments of the MHC DQA gene in woolly mammoth samples radiocarbon dated to before and after a well-documented bottleneck that took place about ten thousand years ago. Our results indicate a decrease in observed heterozygosity and number of alleles, suggesting that genetic drift had an impact on the variation on MHC. Based on coalescent simulations, we found no evidence of balancing selection maintaining MHC diversity during the Holocene. However, strong trans-species polymorphism among mammoths and elephants points to historical effects of balancing selection on the woolly mammoth lineage.

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author
; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Animals, Evolution, Molecular, Extinction, Biological, Genes, MHC Class II, Genetic Variation, Mammoths/genetics, Selection, Genetic, Sequence Analysis, DNA
in
Scientific Reports
volume
6
article number
25274
publisher
Nature Publishing Group
external identifiers
  • scopus:84965171592
  • pmid:27143688
ISSN
2045-2322
DOI
10.1038/srep25274
language
English
LU publication?
no
id
b3151972-a1d0-40f6-bc5e-9b24d0e47662
date added to LUP
2024-10-10 15:58:35
date last changed
2025-01-03 12:22:19
@article{b3151972-a1d0-40f6-bc5e-9b24d0e47662,
  abstract     = {{<p>According to the nearly-neutral theory of evolution, the relative strengths of selection and drift shift in favour of drift at small population sizes. Numerous studies have analysed the effect of bottlenecks and small population sizes on genetic diversity in the MHC, which plays a central role in pathogen recognition and immune defense and is thus considered a model example for the study of adaptive evolution. However, to understand changes in genetic diversity at loci under selection, it is necessary to compare the genetic diversity of a population before and after the bottleneck. In this study, we analyse three fragments of the MHC DQA gene in woolly mammoth samples radiocarbon dated to before and after a well-documented bottleneck that took place about ten thousand years ago. Our results indicate a decrease in observed heterozygosity and number of alleles, suggesting that genetic drift had an impact on the variation on MHC. Based on coalescent simulations, we found no evidence of balancing selection maintaining MHC diversity during the Holocene. However, strong trans-species polymorphism among mammoths and elephants points to historical effects of balancing selection on the woolly mammoth lineage.</p>}},
  author       = {{Pečnerová, Patrícia and Díez-Del-Molino, David and Vartanyan, Sergey and Dalén, Love}},
  issn         = {{2045-2322}},
  keywords     = {{Animals; Evolution, Molecular; Extinction, Biological; Genes, MHC Class II; Genetic Variation; Mammoths/genetics; Selection, Genetic; Sequence Analysis, DNA}},
  language     = {{eng}},
  month        = {{05}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Changes in variation at the MHC class II DQA locus during the final demise of the woolly mammoth}},
  url          = {{http://dx.doi.org/10.1038/srep25274}},
  doi          = {{10.1038/srep25274}},
  volume       = {{6}},
  year         = {{2016}},
}