Actually Chris, there is some evidence, mostly circumstantial, that the
Domestic Ferret was not derived form the European Polecat (perhaps crossbred
at a later date).  I wish I had my references (did a real no-no and loaned
out my only copies) so I could verify this, but I'll go on best memory.
 
    The Domestic Ferret has a larger forebrain and skull than the English
Polecat.
    The E.P. is able to locate objects in space by sound; the D.F is not.
 (Click something near an E.P. and it will wheel around and face the sound;
while the D.F. will be attracted by the sound but have difficulty locating
it.)
     The E.P. can see in (I believe it's) in three colors; the D.F.  can only
distinguish one (red.)
     There are significant differences in the eyes and their ability to see
in 3-D up close.
     I was led to understand the the number of chromosomes differ in the E.P.
and the D.F. (but for this I'd have to look at the original reference.)
     And, I believe, that the breeding cycles differ significantly (the E.P.
female will go out of heat if not bred).
 
I think there were several more differences, but I just can't remember them.
 I wish I had the references at hand, but I remember thinking while reading
the list, that it would be unlikely for human breeders to have purposely
selected these traits to pass on to offspring.  It seemed more likely that
these differences were the result of differentiation during a long period of
isolation.  Remember that the fact that they can interbreed does not mean
that they are the same species.
 
Also, and I look to experts to verify this one, the Red-Eyed White and the
Albino are not the same "color".  There is a difference in the pigmentation
of the eyes.  The true albino has no pigment.  The Red-Eyed White does, and
some believe that this represents something closer to the "original" line of
the North African Mustela from which the Domestic Ferret was developed.  The
theory goes that this Red-Eyed White was later cross- bred with the European
Polecat (and perhaps other Mustela) to develop the many colors that we have
today.  Sort of like the Wolf-Hybrid that is becoming popular in some
sections of the U.S.
 
There was a theory for a while that the DF might have originated from the
Siberian Stepp Polecat, but recent genetic testing disproved this.
 
Dick B.  -  hoping I didn't mis-remember too much
 
[_Please_ find your sources, and type up a summary.  And include the
references!]
 
[Posted in FML issue 0965]