The genetic basis of discrete and quantitative colour variation in the polymorphic lizard, Ctenophorus decresii

Katrina J. Rankin*, Claire A. McLean, Darrell J. Kemp, Devi Stuart-Fox

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    30 Citations (Scopus)
    56 Downloads (Pure)

    Abstract

    Background: Colour polymorphic species provide invaluable insight into processes that generate and maintain intra-specific variation. Despite an increasing understanding of the genetic basis of discrete morphs, sources of colour variation within morphs remain poorly understood. Here we use the polymorphic tawny dragon lizard Ctenophorus decresii to test simple Mendelian models for the inheritance of discrete morphs, and to investigate the genetic basis of continuous variation among individuals across morphs. Males of this species express either orange, yellow, orange surrounded by yellow, or grey throats. Although four discrete morphs are recognised, the extent of orange and yellow varies greatly. We artificially elevated testosterone in F0 females and F1 juveniles to induce them to express the male throat colour polymorphism, and quantified colour variation across the pedigree. Results: Inheritance of discrete morphs in C. decresii best fit a model whereby two autosomal loci with complete dominance respectively determine the presence of orange and yellow. However, a single locus model with three co-dominant alleles for orange, yellow and grey could not be definitively rejected. Additionally, quantitative expression of the proportion of orange and yellow on the throat was strongly heritable (orange: h2 = 0.84 ± 0.14; yellow: h2 = 0.67 ± 0.19), with some evidence for covariance between the two. Conclusions: Our study supports the theoretical prediction that polymorphism should be governed by few genes of major effect, but implies broader genetic influence on variation in constituent morph traits.

    Original languageEnglish
    Article number179
    Pages (from-to)1-14
    Number of pages14
    JournalBMC Evolutionary Biology
    Volume16
    DOIs
    Publication statusPublished - 6 Sept 2016

    Bibliographical note

    Copyright the Author(s) 2016. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

    Keywords

    • Animal model
    • Colour polymorphism
    • Heritability
    • Image analysis
    • Mendelian
    • Microsatellite
    • Quantitative trait
    • Testosterone

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