Scientists Temporarily Reverse Feather Evolution in Chickens
By tweaking a key gene, researchers briefly gave chicken feathers a more dinosaur-like appearance, but the changes didn’t last.
Turning Back Time on Feathers
A new study explored how feathers first evolved by inhibiting a gene in chicken embryos, causing their feathers to develop into simpler, tube-like structures—similar to the proto-feathers found on dinosaur ancestors 250 million years ago.
However, the effect was temporary. The chickens hatched with patchy, underdeveloped feathers, but within weeks, their plumage returned to normal.
The Role of the “Sonic Hedgehog” Gene
This experiment builds on previous research showing that tweaking certain genes can turn scaly chicken feet feathery. However, reversing feather evolution proved to be much more difficult.
At the heart of this transformation is the Sonic Hedgehog gene, which guides embryonic development across species. The researchers injected an inhibitor of this gene into developing chicken embryos at nine days old, stunting feather growth and reducing their complexity.
Yet by day 17, as the inhibition wore off, feathers started recovering. By the time the birds molted at 49 days old, their new feathers developed normally, highlighting how robust feather genetics have become over millions of years of evolution.
What This Means for Evolutionary Science
Despite the temporary nature of the experiment, the study provides valuable insight into feather evolution. Scientists now know that the Sonic Hedgehog gene played a crucial role in both the emergence of proto-feathers and their later diversification.
“The big challenge now,” said study co-author Michel Milinkovitch, “is to understand how these genetic interactions changed to allow for the emergence of proto-feathers early in the evolution of dinosaurs.”
This research brings scientists one step closer to unraveling the mystery of how feathers evolved from simple structures into the diverse forms seen in modern birds today.