Hair, Feathers And Scales Evolved From A Single Reptilian Ancestor

Posted: Jun 25 2016, 1:07am CDT | by , Updated: Jun 26 2016, 7:29am CDT, in News | Latest Science News


Hair, Feathers and Scales Evolved from a Single Reptilian Ancestor
Three variants of bearded dragon lizard used for the study. Credit: Michel C. Milinkovitch

Scientists have found an evolutionary link between apparently seperate features hair in mamamls, feathers in birds and scales in reptiles.

Scientists have found an evolutionary link between mammalian hairs, bird’s feathers and reptilian scales. According to new research, these three apparently distinct features evolved from a single shared ancestor whose signatures can be traced at their early stages of embryonic development.

This common ancestor was an ancient reptilian which was thought to have unusual scale-like structures all over its body. However, they are unable to pinpoint the exact species as of right now. The analysis of embryonic development suggests that the scales on reptilian creature were grown out of an anatomical structure called placode and it is identical to what has developed hairs in mammals and feathers in avian. 

Placode is the thickening of skin which shows up differently in different creatures. The finding baffled scientists since it was long thought that birds and mammals evolved separately from two different lineages of reptile. It’s probably the lack of evidence that has confused scientists over the years. But with the recovery of more evidences, they believe some species of dinosaurs might have covered in feathers unlike characteristic scales. 

For the new study, researchers from University of Geneva and the Swiss Institute of Bioinformatics analyzed the skin morphology and molecular characteristics during embryonic development in Nile crocodiles, corn snakes and bearded dragon lizards and concluded that birds, mammals and reptiles all got their placodes from the same ancient reptilian ancestor. The latest findings add weight to the previous research presented by a team of Yale University in 2015.

Our study not only provides new molecular data that complement the work of the American team but also reveals key microanatomical facts. Indeed, we have identified in reptiles new molecular signatures that are identical to those observed during the development of hairs and feathers, as well as the presence of the same anatomical placode as in mammals and birds,” said Michel C. Milinkovitch, an evolutionary developmental biologist from the University of Geneva in Switzerland and one of authors of the study.

“This indicates that the three types of skin appendages are homologous: the reptilian scales, the avian feathers and the mammalian hairs, despite their very different final shapes, evolved from the scales of their reptilian common ancestor.”

The findings of the study were published in Science Advances.

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Hira Bashir covers daily affairs around the world.




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