The hair on our heads is a lot closer than we think to scales and feathers.
In a remarkable revelation, scientists have discovered where feathers, scales and even hair came from — and it’s a pretty fascinating evolutionary story.
Scientists from the University of Geneva published a study in the journal Science Advances detailing a mutated gene that is responsible both for the bearded dragons losing its scales as well as allowing birds to develop feathers and mammals to develop fur and hair.
Feathers, scales and hair could not look any more different in reality, but they actually start from a common origin. They all use the same common structure, and simply diverged greatly.
It’s a tall order to investigate the origins of these features, because unlike bones, they don’t last long after the death of the creature and thus they are harder to study. So scientists have resorted to studying developing embryos to figure out how they evolved.
They found that early in embryonic development, feathers and fur are very similar, beginning as anatomical placodes on the skin. This is not surprising since birds and mammals evolved from a common ancestor more than 300 million years ago. But as it turns out, the ancestor was also the precursor to modern reptiles, and repitles and birds are actually more closely related. But since reptiles didn’t have these placodes, scientists were stuck — until researchers found that a mutation that prevented scales from developing on the naked bearded dragon was in a gene also responsible for feathers and fur.
“The next challenge for the Swiss team, and many other researchers around the world, is to decipher the fine mechanisms explaining the diversity of forms of skin appendages,” the statement reads. “How has the ancestral scaly skin given rise to the very different morphologies of scales, feathers and hairs, as well as the astonishing variety of forms that these appendages can take? These future studies will hopefully fine-tune our understanding of the physical and molecular mechanisms generating the complexity and the diversity of life during evolution.”
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