A gene that allows birds to produce the color red in their beaks and retinas have been identified by scientists.
The color red has been widely associated as a signal for communication in the animal kingdom. Particularly, this characteristic is used to attract mates, as female birds are said to be generally attracted to males with beaks that have a brighter red color.
The mentioned features of the color red are particularly present among zebra finches, and in a new study, researchers were able to identify, for the first time, the genes that enable them to generate the all-important red pigment in their bodies.
From Yellow To Red
Birds like zebra finches have yellow pigments called carotenoids in their bodies due to their seed and insect diet. In the past, scientists believed that bird species have a way of translating these yellow pigments into red ones called ketocarotenoids. However, the exact mechanisms for this event has been unknown.
To investigate, a group of researchers looked into the genes of wild zebra finches with red beaks and captive ones with mutant, yellow beaks due to a recessive gene.
They were able determine a group of three genes in the wild birds that were not found or changed in the genetic region of the yellow-beaked birds.
The said genes encode enzymes that are vital in disintegrating and processing toxic compounds, mainly in the liver of vertebrates. In humans, the said enzymes are highly linked with drug metabolism.
The genes are also known to have a crucial part in detoxification. Such a fact suggests how the color red may be a powerful indication of mate quality, as it reveals whether a bird can clean hazardous substances in its body.
The concept supports the idea that an evolved trait may result in better species outcomes. In this case, the birds have better abilities to deal with toxic substances.
The team also found the said gene cluster in the retina of the birds.
"It was quite a surprise that the same genes are involved both in seeing red colors and making red coloration," says study author Nick Mundy.
Now, the team is looking at further working on the genetics of red coloration in other species, particularly in widowbirds and bishops.
The study was published in the journal Current Biology on May 19.