Re: [Re: Origin of feathers]

[Jonathon Woolf <jwoolf@erinet.com>]

Dinogeorge wrote:

> In a message dated 98-04-10 03:05:59 EDT, jjackson@interalpha.co.uk writes:
>
> << >
>  >What is a feather. To put it generally a feather is simply a modified
>  scale.
>
>  I thought it had been decided it wasn't.  (Dinolist passim.) >>
>
> As far as I know, feathers are an evolutionary novelty, not a modification of
> an existing structure--unless, perhaps, the keratinous covering of early-
> archosaur scutes was modified into feathers. Anyone know of any comparative
> analyses of the chemical compositions of croc scute keratins with feather
> keratins?

Interesting.  I was under the impression that feathers are homologous to scales,
and have been known to be homologous to scales for a couple of decades.  The 
same
ectodermal cells in a chick embryo can develop into either feathers or scales
depending on the chemical stimuli from the underlying mesodermal cells.

-- JSW