One way to identify the important mechanistic links between metabolism and longevity is to examine the genomes of unusually long-lived species. This has long been underway for naked mole rats and some smaller bats, species that live many times longer than similarly sized near relatives. The same sort of longevity occurs in parrots; other birds of their size live for perhaps a decade or two, but parrots exhibit a similar life span to that of humans, given a safe and supportive environment. Scientists here report on their initial investigations of the parrot genome, and a comparison with less long-lived birds. As for the case for all similar research, it remains an open question as to whether any of the findings will turn out to be of practical use when it comes to developing the means to significantly lengthen healthy human life spans.
Parrots are one of the most distinct and intriguing groups of birds, with highly expanded brains, highly developed cognitive and vocal communication skills, and a long lifespan compared to other similar-sized birds. Yet the genetic basis of these traits remains largely unidentified. To address this question, we have generated a high-coverage, annotated assembly of the genome of the blue-fronted Amazon (Amazona aestiva) and carried out extensive comparative analyses with 30 other avian species, including 4 additional parrots.
We identified several genomic features unique to parrots, including parrot-specific novel genes and parrot-specific modifications to coding and regulatory sequences of existing genes. We 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. 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.
We also identified brain-expressed, parrot-specific paralogs with known functions in neural development or vocal-learning brain circuits. Intriguingly, parrot-specific changes in conserved regulatory sequences were overwhelmingly associated with genes that are linked to cognitive abilities and have undergone similar selection in the human lineage, suggesting convergent evolution. These findings bring novel insights into the genetics and evolution of longevity and cognition, as well as provide novel targets for exploring the mechanistic basis of these traits.