Does it Scale?

You may not think that your hairy human skin has much in common with a fish’s tough scales but you’d be wrong. Although skin and scales look very different, they have similar origins during early development. Our hairy skin starts from an embryonic tissue known as ectoderm, setting up a pattern of hair follicles and sweat glands in response to genetic signals. Ectoderm patterning also gives rise to feathers in birds and scales in reptiles. Researchers have now discovered the same process at work as fish makes scales by studying the genes involved in skin development in these growing zebrafish. The same genes and patterns also turn up as birds grow feathers, mammals produce fur and reptiles make scales. Discovering that the same molecular mechanisms are at work across such a diverse group of animals suggests a single shared origin for skin patterning, dating back more than 300 million years.

Written by Kat Arney

Kat Arney

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Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image from work by Andrew J Aman, Alexis N Fulbright and David M Parichy
• University of Virginia, Charlottesville, VA, USA
• Image originally published under a Creative Commons Licence (BY 4.0)
• Published in BioRxiv, April 2018