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Re: More on Birds, dinosaurs, and digits

On Mon, 1 Dec 1997 celyle@iupui.edu wrote:

> On Sun, 30 Nov 1997, Toby White wrote:
> > (2) The chicken pes clearly has five
> > digits at some points in development.
> I've always assumed that hyperdactylics
> are random mutations (aside from whales and icthyosaurs, etc.) yet unless
> the Dorking's extra toe is actually it s fifth, it would appear that this
> fluke is a norm for this breed.  Anyone know more?

This isn't really helpful as far as that hen goes, but hyperdactyly or
polydactyly does seem to be random in most cases.  The only cases I can
think of are (as you mentioned) whales and ichthyosaurs AND breeds of
animals designed by humans.  There is a breed of goat herding dog (huge
white animals) that have an extra toe on their hind feet.  This is
actually a sign their being "pure-blooded".  In my experience, the extra
digit (I believe in this animal, it is the prepollex) is usually tender.
I don't remember off hand, but there may have been another species as well
that has a constructed breed with an extra toe.  These along with the hen
you write of seems to indicate to me that the hyperdactyly may be
prevalent when humans are controlling the breeding patterns.