Humans Have DNA For Making Feathers

Siberian Turkamanian Eagle Owl by Chris Paul. Via NatGeo.

We’ve always found feathers fascinating, both from an aesthetic and a biological perspective. Recently, the Cornell Lab of Ornithology’s bird guide website AllAboutBirds uploaded an interactive page solely focused on feathers, which is quite a wonderful mine of interesting information, cool animation, and amazing videography. But now, about a month late, we’ve learned that DNA researchers working on the genetic recipe for feathers have found that the sequences responsible for most of the steps involved in creating feathers are actually much, much older than feathers themselves. This indicates that we humans should have a sizable chunk of the feather-making genetic recipe as well! Carl Zimmer reports for the Phenomena section at National Geographic’s website:

Feathers are like eyes or or hands. They’re so complex, so impressive in their adaptations, so good at getting a job done, that it can be hard at first to believe they evolved. Feathers today are only found on birds, which use them to do things like fly, control their body temperature, and show off for potential mates. The closest living relatives of birds–alligators and crocodiles–are not exactly known for their plumage. At least among living things, the glory of feathers is an all-or-nothing affair.

But the more we get to know feathers, the more we can appreciate how they evolved. The general rule is that complex things–be they feathers, hands, or eyes–take a very long time to evolve. As I wrote in National Geographic in 2011, the fossil record has gone a very long way in helping us to understand how feathers took on the form we see today. Birds evolved from dinosaur ancestors, and those ancestors already had feathers. Feathers started out as simple filaments, turning to fuzz, and then diversifying into a lot of different forms–including the ones that eventually let birds take to the air.

A sampling of feathered dinosaurs and early birds. Xing Lida/National Geographic

Now a new study in the journal Molecular Biology and Evolution offers an even deeper look into the history of feathers. Instead of looking at fossils, the scientists look at the genetic recipe for feathers written in the DNA of birds. It turns out that a lot of that recipe already existed hundreds of millions of years before anything vaguely resembling a feather existed on Earth. In fact, you, my fine unfeathered friend, have most of the genetic information required for making feathers, too.

Scott Edwards, a Harvard ornithologist, and his colleagues couldn’t have carried out this study even a few years ago, because scientists have only recently figured out a lot of the details of how feathers develop. Bird embryos starts out featherless. But in their skin, they develop lots of tiny blobs of cells known as placodes in which cells are switching on genes in a distinctive pattern. The reason that certain genes switch on in the placodes and others don’t is that genes have little on-off switches near them. If a particular combination of proteins lands on a gene’s switch, the gene will start making a protein of its own.

You can read the rest of Zimmer’s original article here.

One thought on “Humans Have DNA For Making Feathers

  1. Pingback: Snowy owls news update | Dear Kitty. Some blog

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