By Rory GallowayScience writer
22 November 2017
The genes that caused scales to become feathers in the early ancestors of birds have been found by US scientists.
By expressing these genes in embryo alligator skin, the researchers caused the reptiles' scales to change in a way that may be similar to how the earliest feathers evolved.
Feathers are highly complex natural structures and they're key to the success of birds.
But they initially evolved in dinosaurs, birds' extinct ancestors.
Leading the study, Professor Cheng-Ming Chuong told the BBC that this discovery links important recent palaeontological finds with modern biology, in understanding feather evolution.
Birds have had feathers for as long as they have existed as a group and Professor Chuong couldn't study primitive examples of feathers in any living animals.
"In today's existing reptiles, the one more similar to dinosaurs is actually the alligator, belonging to the Archosaur group," said Prof Chuong from the University of Southern California, in Los Angeles.
Dinosaurs and birds also belong to this wider group of "Archosaur reptiles"; Prof Chuong wanted to investigate whether the feather-forming genes he had identified in birds could change those scales into feathers. So he set out to turn on these genes in the skin of alligator embryos.
"You can see we can indeed induce them to form appendages, although it is not beautiful feathers, they really try to elongate" he explained of the outcome. They are likely similar to the structures on those feather-pioneering dinosaurs 150 million years ago.