Roseate finches are Colorado’s high-mountain specialists, and researchers want to know why

Mountaineers venturing high in the Colorado Rockies have likely seen medium-sized brown and pink birds rummaging through snow patches for insects and seeds. These altitude specialists are the roseate finches, a type of bird that evolved to survive in some of the most rugged places in North America.

Researchers are now beginning to unravel some of the mysteries surrounding these unique birds, including the genetic bases that allow them to survive at elevations up to 14,000 feet and help determine their feather colors.

Their findings suggest that the three recognized species of North American rose finch – the grey-crowned rosefinch, the black rosefinch and the brown-headed rosefinch – may have evolved within the last 250,000 years, which is a period relatively short in evolution. terms.

The scientists shared more details of their work in a new paper recently published in the journal. Evolution.

“These results add to the way we think about population divergence and speciation,” said lead author Erik Funk, who recently earned his Ph.D. in evolutionary biology from the University of Colorado Boulder and now works as a postdoctoral fellow at the National Science Foundation at the San Alianza de Vida Silvestre del Diego Zoo.

understanding biodiversity

Even before Charles Darwin published his theory of evolution by natural selection in 1859, scientists had long pondered Earth’s rich biodiversity. How and why are there so many different types of life on the planet? It’s a question they haven’t fully answered yet, but thanks to recent advances in genetic sequencingresearchers now have new tools to dig deeper.

As a backpacker and climber, Funk has spent a lot of time in the mountains of Colorado and California, where he’d often spot rosy finches flitting about. But while they often inhabit and breed in elevated regions of the Rocky Mountains and Sierra Nevada, they also breed at sea level, such as along the Alaskan coast and between the Aleutian and Pribilof Islands.

In addition to these differences in breeding habits, birds have different colors and patterns of feathers. Some have brown body feathers, while others have black ones. Some have a gray patch on the crown or cheeks, while others do not.

Funk wondered if analysis of bird genomes could help explain some of these differences.

“We wanted to understand: Can we identify genetic regions What are responsible for the plumage color differences that exist in rosy finches?” he said. “And there’s also this question about elevation differences. Do the birds that live in Colorado have some unique genetic differences that allow them to live in high elevations What don’t birds that live at sea level have?

Using blood and tissue samples from the University of Alaska Museum of the North, the Denver Museum of Nature and Science, and a 2018 field study, Funk created a whole genome dataset encompassing the full geographic range and all variable observable features of North American rosy finches. After analyzing the data, he identified unique genomic regions and possibly specific genes– which are probably playing a role in the differences in bird traits.

For example, he found genetic differences between birds with and without gray cheek patches in a region of the genome that influences melanin pigments, which give color to feathers, hair, skin and eyes. By comparing birds that breed at high altitudes with those that breed at low altitudes, he found genetic differences in a region that contains genes that play a role in a cell’s ability to operate at different oxygen levels.

The genes you linked to the traits are all located in different regions of the bird genome, which means they can rearrange over time to form new combinations of traits. This supports the theory that different populations of rose finches likely evolved over a relatively short period of time.

“In general, we think that speciation takes a long time, on the order of millions of years,” Funk said. “But if all this variation already exists within rosy finches, and the genome is able to recombine these different genes to produce new combinations of traits, it could potentially happen much faster. It’s a cool way to think about how different traits or combinations of traits might be able to evolve and might have implications for the speed at which populations diverge and new species are generated.”

More knowledge, more effective conservation efforts

Overall, the findings add to scientists’ understanding of biodiversity. But beyond that, they can also help inform conservation decisions in the face of human-caused climate change.

Brown-headed rosy finches, which live primarily in Colorado, are experiencing population declines and as such have been identified by Colorado Parks and Wildlife as a species of greatest need for conservation.

To help stabilize or increase bird numbers, scientists and conservationists want to know as much about them as possible, and even genetic knowledge could be useful.

“Understanding what led to the rapid generation of these different phenotypes, how they are related, and the genetic variations that underlie them, allows us to better understand how quickly evolution can generate differences,” said study co-author Scott Taylor, a CU associate. Boulders. professor of ecology and evolutionary biology and director of the Mountain Research Station.

“And perhaps understanding that will help us better understand how these populations might respond to population collapses or changing environments in the future.”