Scientists have managed to breed chickens with feathers like dinosaurs

As part of a study of feather evolution, scientists have managed to temporarily change the appearance of chickens, bringing their plumage closer to what it probably was like on the ancestors of dinosaurs.

Experts suppressed the work of the key Sonic Hedgehog gene at the stage of embryonic development. This allowed them to change the structure of the feathers – they began to resemble tubular protofeathers, which are believed to have existed on dinosaurs in the Triassic period about 250 million years ago. After hatching, the chicks had slow feather development and bare patches of skin. However, after a few weeks, their feathers returned to their normal appearance, like other birds of their species.

The goal of the experiment was to find out when and how feathers appeared. Previously, scientists also made changes to the Sonic Hedgehog gene to produce chickens with feathers on their feet. The results showed that while the development of scales on the feet can be permanently changed, turning them into feathers, then intervention in the formation of the plumage itself leads only to temporary changes. According to Michel Milinkovic, a professor at the University of Geneva, this indicates that over the course of evolution, the gene network responsible for feather growth has become particularly stable and able to compensate for external influences.

Although the scientists were unable to create a chicken with full “dinosaur-like” plumage, the study helped to better understand the role of the Sonic Hedgehog gene in the evolution of feathers. As co-author of the work, Rory Cooper, an employee of the University of Sheffield, noted, the first feathers were simple tubular growths, and only in the course of evolution did they take on different forms – from soft fluff to the bright plumage of peacocks.

To observe the development of feathers in embryos, the researchers used the method of light sheet fluorescence microscopy for the first time. This technology uses lasers to obtain detailed images of samples.

On the ninth day of embryonic development, the future chick begins to form feather rudiments, the so-called placodes. These formations resemble small bumps and later develop into full-fledged feathers using keratin, the same protein found in human hair and nails. At this point, scientists introduced an inhibitor that blocked the Sonic Hedgehog gene. As a result, feather growth slowed down and they lost their complex structure. But by the 17th day, feather development had partially recovered, and after hatching, the chicks soon changed their plumage to normal.

The study confirmed that the Sonic Hedgehog gene plays a key role both in the transformation of primitive feathers into modern ones and in the formation of different types of feathers in birds.

“The next task is to find out how the interactions of these genes changed in the early stages of evolution, which allowed feathers to appear in the ancestors of dinosaurs,” said Michel Milinkovic.