While researching and educating myself about evolution, I've come across an interesting claim that I'd like to learn more about, but so far, I've only been able to find the claim and no sources or evidence. For example consider following:

Now I did find another claim which provided a source, but it appears to be saying something different (the opposite in away), and the sited link (Poling, J. 1996. Feathers, scutes and the origin of birds. Dinosauria on-line. Retrieved April 11, 2007) is broken:

Experiments show that the same protein (when missing before birth) that causes bird feet to stay webbed, causes bird scutes and scales to become feathers (Poling 1996) - New World Encylcopedia

I'm aware that the debate on the origin of feathers (and flight) is ongoing among scientists with several hypotheses being proposed, as very well described in a recent National Geographic article from Feb 2011. While I am interested in this in general, I'm currently trying to make sense of the claims mentioned above. Can they be substantiated, or are they baseless? I've spent about an hour searching online and haven't found anything but ambiguity (which scientists, which protein/mutation, etc).


I also found this related claim at evolutionwiki.org, emphasis mine:

Scientists have actually discovered that the same protein (when missing at birth) that keeps bird feet webbed causes reptile scales to become feathers. Birds thus could be descended from any number of reptilian species, also clear and powerful evidence for the evolution of birds from reptiles.

This claim here seems to be a variation of the one above, but with reptile being used instead of bird. It is for reasons like this, and for lack of references, that I am very skeptical of these claims. They give the impression that a key gene mutation that stops the production of a protein will cause chicks to be born without feathers and instead contain scales. Or that again, a key gene mutation that stops the production of a protein will cause a developing reptile to be born with feathers instead of scales. This later claim seems even more extraordinary if you ask me.

  • Not answer, but an observation you might be interested in. If you look at the feet of a bird, you will see that it has scales. Aug 21 '12 at 17:27
  • @Matt that has been known for at least 25 years(I learned about it in high school biology). It is probably going to be hard to find online sources of recent experiments for something that was discovered and proven repeatedly in the early days of DNA Experimentation. If you are truely interested in it I would explore 70's and 80's Genetics text books from the library.
    – Chad
    Aug 21 '12 at 19:30
  • @Chad, that's interesting, after a bit further searching I come across some scientific papers that points to the protein Keratin perhaps being responsible for the scenario of my question (see here (1978), and here (1986)), but the vocabulary of the papers' abstract is beyond my full comprehension.
    – Matt
    Aug 21 '12 at 20:00

This is not an exhaustive or conclusive answer, but I've come across experiments that show the following:


The references show that the scales on the feet of some birds can develop feathers instead, and that some areas where feathers normally are can have scales instead (though this later claim I'm not sure is substantiated enough, at least in the reference sited - Leah Lefler's article).

Either way, it seems to me that the claims shown in the question have a measure of truth to them, some more so than others, but are very simplified claims, likely even containing errors, that could cause a person to draw distorted conclusions. For example, the research certainly doesn't show that a baby lizard can be born today with feathers instead of scales.

Recombinant lizard/chick experiments http://htmlimg1.scribdassets.com/6v5wbrwp4w1jbq4k/images/8-a6811b38ed.jpg

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