From: "Dan Meliza" 
Subject: RE: (urth) Marble's prophecy
Date: Thu, 21 Mar 2002 09:40:52 -0800


Hi Marc,

I haven't had a chance to look at the pics (qualifying exams, alas), but
Xenopus laevis is naturally polyploid (making it difficult to make
transgenic animals, for anyone who cares), and N varies greatly between
species in the genus (something like 12N for one of those buggers).  I think
it might be a little spurious to claim that simply doubling the number of
chromosomes would double limb count.  Development is a lot more complex than
that.

best,
dan


-----Original Message-----
From: maa32 [mailto:maa32@dana.ucc.nau.edu]
Sent: Monday, March 18, 2002 9:19 PM
To: urth@urth.net
Subject: (urth) Marble's prophecy

[snip]

Now that I look at it again, I see the one one the
left is 2N, the one on the right is 4N.  Note that the front limbs of the
frog
also have three little digits that should be one (like three psuedo-hands or
something)  If you click on the arrows at the bottom of that page of the
presentation, you can see the whole 31 slides.  There are other hybrid
species
produced through polyploidy, including lizards and flies.  The flies also
have
a doubling of the hind legs that is pretty interesting if you advance a few
slides.

Marc Aramini



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