Dinosaurs no longer roam the planet – unless you count birds. Recent discoveries have revealed many dinosaurs once had feathers, and birds are actually dinosaurs that have evolved over time. But we don’t really know how feathers evolved. A recent study led by University of Southern California (USC) researchers involving alligator and chicken genes may offer new insight.
Feathers and scales are comprised of keratin, and both are part of skin growth, so scientists have surmised they might have a shared evolutionary history. But the nature of that history is still a mystery. A dinosaur unearthed in 2014 in Siberia appeared to possess feather-like filaments, some growing out of scales – leading researchers to think feather-like structures might have evolved from modified scales. So the USC-led team took genes they think might be important in the development of feathers and had them expressed in chicken and alligator embryos while feathers and scales, respectively, developed. They also identified new genes that regulate the development genes and altered the amount of their activity, according to The Guardian.
The researchers produced new types of modified scales, revealing relatively simple changes to some genes can cause alligator early scale development to produce things like the ancestral feathers of non-avian dinosaurs. The Guardian said it’s not a large step from the feather-like structures to something similar to a true early feather. Add the idea that early proto-feathers that gave advantages to their owners would have developed more under natural selection, and it’s not a massive leap to suggest feathers could have formed rather easily.
Modifying genes in chickens led to an array of feather forms, including ones seen in dinosaurs, narrowing the gap between feather and scale from a creature with feathers. We still have a long way to go in our understanding, but this recent work could offer some clues. More gene tweaks could potentially reveal the pathway from scale to feather.
The journal Molecular Biology and Evolution published the research this month; scientists from institutions in Taiwan, China, and Louisiana contributed to the work.
Via The Guardian