From the colorful parades of Rio de Janeiro’s Carnival to the shoulders of pirates, parrots are known around the world for their vibrant feathers. With hues that range from bright yellows to rich reds and greens, these birds are beloved for their striking appearance. Yet, despite their visual appeal, the exact way parrots create such unique colors has long puzzled scientists. Now, a recent study in the journal Science has brought new insight, revealing a genetic “switch” in parrot DNA that controls their wide-ranging color palette. The study was led by an international team of scientists from BIOPOLIS-CIBIO in Portugal, with key contributions from researchers at The University of Hong Kong.
According to Professor Simon Yung Wa Sin, a co-author from the University of Hong Kong, parrots stand out among birds not just for their beauty, but also for their unusual approach to creating color. While other birds can also produce yellows and reds, parrots evolved their own pigments, called psittacofulvins, to achieve their characteristic vibrancy. These unique pigments, derived from the Greek word for “parrot” and the Latin for “reddish-yellow,” allow parrots to blend colors in ways that no other birds do, producing a range that includes bright yellows, vivid reds, and deep greens. This unique use of pigments has made parrots among nature’s most colorful animals.
Despite their popularity as pets and icons of intelligence and beauty, the molecular mechanics behind parrots’ color diversity had previously been poorly understood. This research, explained by Professor Miguel Carneiro from BIOPOLIS-CIBIO, addresses a question central to evolutionary biology: how does diversity arise in nature? Carneiro points out that answering this question involves exploring the mechanisms behind specific traits—in this case, the spectrum of colors in parrot feathers.
The researchers began by studying various parrot species to examine how they produce yellow and red pigments. They found that these colors in parrot feathers correspond to two unique types of psittacofulvin pigments, absent in other birds. Dr. Jindřich Brejcha from Charles University in Prague, one of the study’s co-authors, notes that while earlier research hinted at two forms of psittacofulvins, this study provides the first clear genetic evidence of their existence.
To explore the role of this genetic “switch” further, the team studied a parrot species with both yellow and red variants: the dusky lory, native to New Guinea. Thanks to local breeders in Portugal, researchers accessed samples of this parrot to study the genetic differences driving its color variations. They discovered that a single protein—an aldehyde dehydrogenase, or ALDH—controls the color shift between red and yellow feathers. This protein, typically used for detoxification in many organisms (including humans, where it helps break down alcohol in the liver), has a new function in parrots: changing pigment intensity.
Dr. Soraia Barbosa from BIOPOLIS-CIBIO explains that parrot feathers have “borrowed” this detox protein to transform red pigments into yellow. The intensity of this ALDH protein activity effectively acts as a dial, shifting feather color from deep red to bright yellow based on its level of expression.
The researchers also examined the rosy-faced lovebird, another parrot species with both green and red plumage patches. This species offered an ideal model for testing the gene that influences feather color. Professor Yung Wa Sin, who led this segment of the study, found that the aldehyde dehydrogenase gene is highly active in feathers with yellow pigments but not in those with red pigments. When this gene expresses at higher levels, it results in a yellow coloration instead of red.
For further confirmation, the team turned to the familiar budgerigar. They examined individual cells involved in feather growth to identify how these cells switch specific genes on or off, affecting pigment production. This study marks the first time scientists have tracked how individual cells manage the expression of this color-changing protein throughout feather development.
In a final step, the team genetically engineered yeast to carry the parrot color gene. The modified yeast successfully produced parrot pigments, showing that this gene alone is sufficient to explain the color transformations seen in parrot feathers. Professor Joseph C. Corbo from Washington University in St. Louis, a co-author of the study, notes that these findings confirm the gene’s key role in controlling yellow and red pigments in parrots.
The discovery sheds new light on how nature evolves complex traits through relatively simple genetic innovations. By “borrowing” a protein typically used for detoxification, parrots have developed a unique mechanism to control feather coloration. According to Carneiro, this research adds a new understanding of evolution, showing that dramatic changes in traits like color can arise from subtle shifts in gene expression. This insight into parrot color not only uncovers the molecular mechanisms behind one of nature’s most colorful birds but also offers a fresh perspective on the evolution of diversity itself.
Source: The University of Hong Kong