proteins, feathers, and scales

[NKING.UCS@smtp.usi.edu (King, Norm)]

Imagine, for the moment, that scales evolved into feathers.  That 
involves quite a structural change.  Couldn't such a change also have 
involved a change in proteins?  After all, all cells in an organism have 
the same genotype, hence are potentially capable of producing any protein 
found in the animal.  With structure changing so much, couldn't the 
dominant protein change, too?

In other words, can protein compositional differences really be used to 
show that feathers are a novelty in birds, rather then being modified 
scales?

There are species out there, I believe called "sibling species," that 
appear to be identical, except their biochemistry is different.  Some 
species of paramecia and fungus are incompatible due to serological or 
other differences, but there is no other way to tell them apart.  The 
point is that their biochemistry changed, but nothing else.  Now, if 
there was such a dramatic structural change in reptilian scales that they 
became feathers, maybe we could expect a change in protein composition 
also.


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Norman R. King                                       tel:  (812) 464-1794
Department of Geosciences                            fax:  (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712                      e-mail:  nking.ucs@smtp.usi.edu