Mystery of How Dinosaur Scales Became Feathers Could Be Explained By...Alligators

Tianyulong confuciusi, a feathered dinosaur. Smithsonian

Scientists have re-created the beginnings of the process that allowed scales of dinosaur-era birds to evolve into feathers.

The early ancestors of modern birds had scales. By identifying the feather-forming genes in modern birds and activating the same ones in alligator embryos, a team of researchers successfully prompted alligator scales to change to feathers. Their feat lends clues to how dinosaur scales first began to change into feathers. A paper describing the findings was published in the journal Molecular Biology and Evolution.

"In human evolution the great achievement is the brain, in birds it is the feathers," lead author Cheng-Ming Choung, a professor in the Department of Pathology at the University of Southern California's Keck School of Medicine, told the BBC.

A 130-million-year-old fossil dinosaur covered with feathers is on display 25 April 2001, at the American Museum of Natural History in New York. STAN HONDA/AFP/Getty Images

Dinosaurs themselves had protofeathers. A previous study found that all dinosaurs could have had them, not just the ones that would evolve into birds.

"It's impossible that they flew," lead author Pascal Godefroit, director of earth and life sciences at the Royal Belgian Institute of Natural Sciences, told the Washington Post when that study was published. "They were bipedal and had long legs with very, very short arms."

There aren't any birds living today that are still equipped with an earlier form of feather; they all evolved to have modern ones. Alligators, though, basically stepped off the conveyor belt of evolution about 8 million years ago, and so studying them can yield clues to dinosaurs.

Archosaurs gave rise to dinosaurs and eventually birds and reptiles, including alligators. Though the similarities alone aren't enough to make an alligator ever sprout wings, Choung's genetic manipulation of alligator embryo skin still appeared to kickstart the early stage of the process.

"You can see we can indeed induce them to form appendages, although it is not beautiful feathers, they really try to elongate," he told the BBC.

Now, the team is collaborating with plastic surgeons to see how their research can be applied to human scar tissue, which often prevents skin structures from developing on the area after it's healed. The findings could be key to skin regeneration therapies that help minimize a scar's appearance.