Life history trade-offs at a single locus maintain sexually selected genetic variation

Johnston, Susan E., Gratten, Jacob, Berenos, Camillo, Pilkington, Jill G., Clutton-Brock, Tim H., Pemberton, Josephine M. and Slate, Jon (2013) Life history trade-offs at a single locus maintain sexually selected genetic variation. Nature, 502 7469: 93-95. doi:10.1038/nature12489

Author Johnston, Susan E.
Gratten, Jacob
Berenos, Camillo
Pilkington, Jill G.
Clutton-Brock, Tim H.
Pemberton, Josephine M.
Slate, Jon
Title Life history trade-offs at a single locus maintain sexually selected genetic variation
Journal name Nature   Check publisher's open access policy
ISSN 0028-0836
Publication date 2013-10
Sub-type Letter to editor, brief commentary or brief communication
DOI 10.1038/nature12489
Volume 502
Issue 7469
Start page 93
End page 95
Total pages 3
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Collection year 2014
Language eng
Formatted abstract
Sexual selection, through intra-male competition or female choice, is assumed to be a source of strong and sustained directional selection in the wild. In the presence of such strong directional selection, alleles enhancing a particular trait are predicted to become fixed within a population, leading to a decrease in the underlying genetic variation. However, there is often considerable genetic variation underlying sexually selected traits in wild populations, and consequently, this phenomenon has become a long-discussed issue in the field of evolutionary biology. In wild Soay sheep, large horns confer an advantage in strong intra-sexual competition, yet males show an inherited polymorphism for horn type and have substantial genetic variation in their horn size. Here we show that most genetic variation in this trait is maintained by a trade-off between natural and sexual selection at a single gene, relaxin-like receptor 2 (RXFP2). We found that an allele conferring larger horns, Ho+, is associated with higher reproductive success, whereas a smaller horn allele, HoP, confers increased survival, resulting in a net effect of overdominance (that is, heterozygote advantage) for fitness at RXFP2. The nature of this trade-off is simple relative to commonly proposed explanations for the maintenance of sexually selected traits, such as genic capture (‘good genes’) and sexually antagonistic selection. Our results demonstrate that by identifying the genetic architecture of trait variation, we can determine the principal mechanisms maintaining genetic variation in traits under strong selection and explain apparently counter-evolutionary observations.
Keyword Sexual selection
Evolutionary genetics
Evolutionary ecology
Evolutionary biology
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Letter to editor, brief commentary or brief communication
Collections: Queensland Brain Institute Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 62 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 68 times in Scopus Article | Citations
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Created: Thu, 03 Oct 2013, 14:08:38 EST by Debra McMurtrie on behalf of Queensland Brain Institute