Researchers from the University of Geneva have successfully transformed chicken scales into feathers by temporarily modifying the expression of the Sonic hedgehog (Shh) gene. This groundbreaking discovery highlights that significant evolutionary changes can occur without extensive modifications to the genome, providing insight into the diverse forms of animal structures. Skin appendages like scales, feathers, and hair possess homologous origins, inherited from a common reptilian ancestor, despite their varied appearances.
In their study, published in Science Advances, the scientists explored how specific alterations in gene expression could lead to the formation of feathers in habitats typically occupied by scales, specifically in chicken embryos. By applying targeted treatments to activate the Shh signaling pathway during embryonic development, the researchers observed the successful creation of down-type feathers in previously scaled areas, which were ultimately replaced by adult feathers.
This transient activation of the Shh pathway illustrates how minor genetic expression changes can trigger complex developmental outcomes. The findings emphasize the potential for understanding evolutionary transitions, suggesting that the mechanisms behind the development of diverse appendages may offer significant insights into the evolutionary history and biological processes shaping vertebrate diversity.
