enzymes/evolution

Brian Foley brianf at med.uvm.edu
Wed Apr 24 14:51:16 EST 1996


: On 1 Apr 1996 elida at parasit.lan.mcgill.ca wrote:

: > I am interested in published examples of proteins which have the same function
: > and do not share primary structures homology and vice-versa, in the context
: > of evolution. If someone could direct me to such references I will appreciate.
: > Elida
: > 

	The developmental genes with homeo domains and paired
domains are good examples.  See for example the Pax1 - Pax8 genes.
They all bind DNA, so they all have sort of the same function.
They use various combinations of homeo domain and paired domain
elements to bind specifically to different promoter elements.
Pax6 controls eye development, and it has been shown that the 
mouse gene, which directs development of a single-lense mammalian eye 
in mouse, can direct the development of a compound insect eye in
Drosophila (the mouse and Drosophila Pax6 genes are highly similar).
	Downstream form the Pax6 gene (regulatory-wise) the eye
lense is developed from epidermal tissue when influenced by the Pax6
gene product.  In some organisms the eye lense crystalins are made
from one type of crystalin protein, and in other organisms the 
eye lense is made from entriely different proteins.  So here
different genes have been recruited to fill the role of making a 
clear cover for the eye.
	See the research of Dr. Walter Gehring for good information
on this topic.
 
--
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*  Brian Foley               *  btf at t10.lanl.gov                   *
*  T-10, MS-K710, LANL       *  http://hiv-web.lanl.gov            *
*  Los Alamos, NM 87545 USA  *  http://www.uvm.edu/~bfoley         *
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