THE GENETIC ARCHITECTURE OF A FEMALE SEXUAL ORNAMENT

Authors

  • Dominic Wright,

    1. Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
    2. IFM Biology, Linköping University, SE 58183 Linköping, Sweden
    3. Department of Medical Biochemistry & Microbiology, BMC, Uppsala University, Box 597, Uppsala, SE-75124 Sweden
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  • Susanne Kerje,

    1. Department of Medical Biochemistry & Microbiology, BMC, Uppsala University, Box 597, Uppsala, SE-75124 Sweden
    2. Department of Medical Sciences, Uppsala University Hospital, Uppsala, SE-751 85, Sweden
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  • Helena Brändström,

    1. Department of Medical Sciences, Uppsala University Hospital, Uppsala, SE-751 85, Sweden
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  • Karin Schütz,

    1. Department of Animal Environment & Health, Section of Ethology, Swedish University of Agricultural Sciences, Skara, S-53223 Sweden
    2. AgResearch, Animal Behaviour and Welfare, Private Bag 3123, Hamilton, New Zealand
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  • Andreas Kindmark,

    1. Department of Medical Sciences, Uppsala University Hospital, Uppsala, SE-751 85, Sweden
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  • Leif Andersson,

    1. Department of Medical Biochemistry & Microbiology, BMC, Uppsala University, Box 597, Uppsala, SE-75124 Sweden
    2. Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Box 597, SE-751 24, Sweden
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  • Per Jensen,

    1. IFM Biology, Linköping University, SE 58183 Linköping, Sweden
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  • Tommaso Pizzari

    1. Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
    2. E-mail: tommaso.pizzari@zoo.ox.ac.uk
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Abstract

Understanding the evolution of sexual ornaments, and particularly that of female sexual ornaments, is an enduring challenge in evolutionary biology. Key to this challenge are establishing the relationship between ornament expression and female reproductive investment, and determining the genetic basis underpinning such relationship. Advances in genomics provide unprecedented opportunities to study the genetic architecture of sexual ornaments in model species. Here, we present a quantitative trait locus (QTL) analysis of a female sexual ornament, the comb of the fowl, Gallus gallus, using a large-scale intercross between red junglefowl and a domestic line, selected for egg production. First, we demonstrate that female somatic investment in comb reflects female reproductive investment. Despite a trade-off between reproductive and skeletal investment mediated by the mobilization of skeletal minerals for egg production, females with proportionally large combs also had relatively high skeletal investment. Second, we identify a major QTL for bisexual expression of comb mass and several QTL specific to female comb mass. Importantly, QTL for comb mass were nonrandomly clustered with QTL for female reproductive and skeletal investment on chromosomes one and three. Together, these results shed light onto the physiological and genetic architecture of a female ornament.

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