New study led by Portuguese scientists unravels the mystery of parrot colours

From Rio's Carnival to pirates’ shoulders, parrots are synonymous with colour for people worldwide.

Now, in a new study published in the journal Science, an international team led by Portuguese scientists from BIOPOLIS-CIBIO and the Faculty of Sciences and Technology of the University of Coimbra (FCTUC) reveals for the first time how a single gene enables parrots to control their wide variety of colours.

"Parrots 'colour' their feathers in a unique way," says Roberto Arbore of BIOPOLIS-CIBIO and co-first author of the study. "Although many birds have yellow and red feathers, parrots use unique pigments called psittacofulvins (from the ancient Greek psittakós for parrot and the Latin fulvus for reddish-yellow). These birds combine these and other pigments to create vibrant colours such as yellow, red, and green, making them some of nature's most colourful animals," Arbore explains.

Known for their colour and intelligence, how this vast palette is created has long puzzled scientists. Miguel Carneiro, from BIOPOLIS-CIBIO and the study's coordinator, adds, "This is a great mystery for both scientists and bird lovers and is central to a key question in biology: how does diversity arise in nature?"

To answer this crucial question, the scientists first showed that in different parrot species, yellow and red colours are consistently produced by two types of pigment unique to birds. They then focused on the rare case of a species where yellow and red individuals coexist in the wild.

Pedro Miguel Araújo, a researcher at FCTUC who co-led the study, says: "We worked with certified bird breeders in Portugal to study the genetics of the Dusky Lory, a species from Papua New Guinea.

The researchers discovered that a single protein, a type of aldehyde dehydrogenase (ALDH) - an important 'tool' for detoxifying complex organisms - drives the colour variation in these lorikeets. In humans, for example, it helps eliminate alcohol from the liver.

Soraia Barbosa, also co-first author from BIOPOLIS-CIBIO, explains: “Parrot feathers 'borrow' this protein to turn red psittacofulvins into yellow ones. This mechanism works like a reverse dimmer switch: the more active the protein, the less intense the red colour.”

To demonstrate this straightforward mechanism, the team used the yellow parrot to examine how each feather cell individually switches specific genes on and off during feather formation—a study never before conducted globally. This enabled them to conclude that a small set of cells controls all the feather colour variations.

The team engineered yeast with this parrot colour gene as a final validation. “Surprisingly, our modified yeasts started producing parrot colours, showing that this gene alone can control the yellow and red pigmentation in parrot feathers.”

"This study shows how cutting-edge biotechnology is increasingly being used to unlock nature's secrets. We now have a better understanding of how these remarkable colours evolve in wild animals through a simple regulatory mechanism that repurposes a detoxification protein," they conclude.

These findings help scientists paint a vivid new picture of species evolution as a process in which complexity arises from simple innovation.

The scientific article is available here.

^{Translation: Diana Taborda}