A genetic mechanism for sexual dichromatism in birds

Małgorzata A Gazda1,2, Pedro M Araújo1,3, Ricardo J Lopes1, Matthew B Toomey4,5, Pedro Andrade1,2, Sandra Afonso1, Cristiana Marques1,2, Luís Nunes2, Paulo Pereira1,2, Sandra Trigo1, Geoffrey E Hill6, Joseph C Corbo4, Miguel Carneiro7,2

  1. CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal.
  2. Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.
  3. MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
  4. Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
  5. Department of Biological Science, University of Tulsa, Tulsa, OK 74104, USA.
  6. Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
  7. CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal. miguel.carneiro@cibio.up.pt.

Abstract

Sexual dichromatism, a difference in coloration between males and females, may be due to sexual selection for ornamentation and mate choice. Here, we show that carotenoid-based dichromatism in mosaic canaries, a hybrid phenotype that arises in offspring of the sexually dichromatic red siskin and monochromatic canaries, is controlled by the gene that encodes the carotenoid-cleaving enzyme β-carotene oxygenase 2 (BCO2). Dichromatism in mosaic canaries is explained by differential carotenoid degradation in the integument, rather than sex-specific variation in physiological functions such as pigment uptake or transport. Transcriptome analyses suggest that carotenoid degradation in the integument might be a common mechanism contributing to sexual dichromatism across finches. These results suggest that differences in ornamental coloration between sexes can evolve through simple molecular mechanisms controlled by genes of major effect.

Presented By Małgorzata A Gazda | ORCID iD

Genetics & Genome BiologyNicholas Liao2020-06 (Jun)