How Do Some Birds Enable Yellow To Red Color Conversion?

Researchers have recognized an enzyme-encoding gene that allows some birds to transform yellow pigments from their diets into bright red. This red color attracts mates or prevents rivals. It is also a depiction of genetic quality, which is a sign of better genes.

Science Daily reports that the findings were printed in Current Biology on May 19. Miguel Carneiro of Universidade de Porto in Portugal explained that to produce red feathers, birds transform yellow dietary pigments known as carotenoids into red pigments then deposit them in the feathers.

He added that birds also accumulate these same red pigments in one of the cone photoreceptor types in their retina to enhance color vision. They found out the gene that code for an enzyme that enables this yellow-to-red conversion in birds. The one responsible for red pigmentation is the CYP2J19, a cytochrome P450 enzyme in chromosome 8.

Another study was conducted researching the genetics of yellow-beaked zebra finches. It was led by Nicholas Mundy, an evolutionary geneticist in the department of zoology at the University of Cambridge and Jessica Stapley, an evolutionary biologist in the plant sciences and animal at the University of Sheffield, according to CS Monitor.

The domesticated zebra finches obtain carotenoids, or yellow pigments through their food, which are seeds. In the study, the researchers have recognized a group of three genes in wild finches that were lost in the same genetic region for "yellow beak" birds. Likewise, the genes in this study determine cytochrome P450s enzymes responsible for metabolizing toxic compounds.

Professor Joseph Corbo, researcher of retinal diseases at the Washington University School of Medicine explained that these findings suggest that nearly all birds have the latent capacity to make red feathers, but in order to actually do so, they must develop the means of expressing (this gene) in the skin in addition to the retina.