Sexual dimorphism in the mosaic Canaries is determined by the gene expression BCO2that this breed inherited from the fiery Siskins. In females it is expressed stronger, which leads to accelerated degradation of pigments in the feathers and makes them less bright. As noted by the authors of the research article for the journal Science, their discovery shows that complex gender differences in the coloration of birds can be governed by just one or a few genes.
For many birds the sexes differ in plumage. Males usually have bright coloration, which serves as an advertisement to females and a warning to competitors. At the same time, females are modest, allowing attract less attention from predators, especially during incubation.
Genetic basis of sexual dimorphism in birds are not well understood yet. To explore this topic more decided team of specialists led by Miguel Carneiro (Miguel Carneiro) from the University of Porto. They focused their attention on an unusual breed of Canaries (Serinus canaria) — mosaic.
For most pet Canaries and their wild ancestors, who still live on the Islands of the Atlantic ocean, sexual dimorphism is not typical. However, in the mosaic of the breed males significantly differ from females: more red areas in the plumage, in particular, there is a red “mask” on the head. This is because in the feathers of males higher the concentration of carotenoid pigments.
Sexually dimorphic Canaries, mosaic, inherited from the fiery South American Siskins (Spinus cucullatus). When these birds are crossed with ordinary Canaries, you get individuals who, regardless of sex painted in bright red color. Another crossing provides birds with a mosaic phenotype and differences in coloration between males and females.