Even though parrots talk up a storm, they can’t tell us how they manage to live so long—much longer than similarly sized birds—or why they display such highly developed cognitive abilities, including tool use, complex social organization, and cooperative problem solving. Perhaps it’s just as well, then, that a team of scientists decided to let the parrot’s genome do the talking.
The parrot in question is the blue-fronted Amazon. For this bird, a high-coverage, annotated genome was assembled by scientists based at Carnegie Mellon University (CMU) and Oregon Health and Science University (OHSU). Then, once the scientists had this genome in hand, they compared it with the genomes of 30 other long- and short-lived birds, including genomes from four additional parrot species.
What did the scientists find? Several genomic features unique to parrots, including previously unknown parrot-specific genes and parrot-specific modifications to coding and regulatory sequences of existing genes. They also discovered genomic features under strong selection in parrots and other long-lived birds, including genes previously associated with lifespan determination as well as several hundred new candidate genes.
Additional details appeared December 6 in the journal Current Biology, in an article titled, “Parrot Genomes and the Evolution of Heightened Longevity and Cognition.” The article’s findings suggest that parrots, which outperform even great apes in several measurements of intelligence, may serve as an excellent experimental model for uncovering the genetic basis of higher cognition.
“We saw that regulatory elements of genes related to brain development and function had similar modifications in humans and parrots,” said the article’s co-senior author, Claudio Mello, Ph.D., a behavioral neuroscientist at OHSU. “That means that some cognitive abilities may have evolved convergently in both humans and parrots.”
Parrots tend to live in large groups, which Dr. Mello speculates may have driven the evolution of traits such as the ability to imitate sounds, complex social behaviors, and other cognitive abilities; their calls are thought to reflect these social structures. Complex social structures are thought to have been a driving force in the evolution of human language as well.
The article’s lead author, Morgan Wirthlin, Ph.D., a computational biologist at CMU, noted that parrots are known to live up to 90 years in captivity—a lifespan that would be equivalent to hundreds of years for humans. She contributed to the study of the parrot’s longevity-related genes. “These genes support a range of cellular functions, including telomerase activity; DNA damage repair; control of cell proliferation, cancer, and immunity; and anti-oxidative mechanisms,” the Current Biology article detailed. “We also identified brain-expressed, parrot-specific paralogs with known functions in neural development or vocal-learning brain circuits.” Some of these genes were previously shown to affect lifespan in worms and flies.
“In many cases,” Dr. Wirthlin pointed out, “this is the first time we’ve connected those genes to longevity in vertebrates.”
The researchers also discovered changes in gene-regulating regions of the genome—which seem to be parrot-specific—that were situated near genes associated with neural development. Those same genes are also linked with cognitive abilities in humans, suggesting that both humans and parrots evolved similar methods for developing higher cognitive abilities.
Parrots tend to live in large groups, which Dr. Mello speculates may have driven the evolution of traits such as the ability to imitate sounds, complex social behaviors, and other cognitive abilities; their calls are thought to reflect these social structures. Complex social structures are thought to have been a driving force in the evolution of human language as well.
“Learning to imitate sounds is the basis of speech in birds and in humans as well,” explained Dr. Mello. “It’s actually a very complex process, and we don’t fully understand how it happens. We know that species incapable of vocal learning will still make sounds if you deafen or isolate them from birth, because their sounds are innate. But isolate or deafen a young parrot, as has been shown in budgerigars, and it will not learn to vocalize properly.”
