A genetic mechanism for sexual dichromatism in birds

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.

Source: ScienceNOW - June 10, 2020 Category: Science Authors: Gazda, M. A., Araujo, P. M., Lopes, R. J., Toomey, M. B., Andrade, P., Afonso, S., Marques, C., Nunes, L., Pereira, P., Trigo, S., Hill, G. E., Corbo, J. C., Carneiro, M. Tags: Evolution, Genetics reports Source Type: news