> To: molecular-evolution at net.bio.net> From: griffin at mailbox.syr.edu (David H. Griffin)
> Subject: Re: Evolution? Can anyone really believe this?
> Date: 19 Jun 1995 13:49:54 GMT
> In article <1995Jun16.134129.17490 at galileo.cc.rochester.edu>
>ttha at uhura.cc.rochester.edu (Tom Thatcher) writes:
> > I think I answered most of this already. I want to correct a
> > misconception, though, it that cells do not move to their location,
> > as you seem to suggest, rather, location determines fate (mostly).
> > A newly divided cell in the embryo's tail doesn't think to itself,
> > "I'm a brain cell, better get a move on."
> I think that cellular movement is an important component of
> development. Certainly in the cellular slime mold, Dictyostelium and
> relatives, cellular movement is an important determinant in
> differentiation and development. The fate of the individual cell,
> whether stalk or spore, is determined by the timing of its movement
> from the free-living amoeba stage into the multicellular animal, the
> grex or slug.
>> Animal embryologists could also supply examples of cellular movement
> during development. Certainly the flat fish, e.g. flounders, provide
> excellent examples of final form being the result of cellular, indeed
> entire organ, movement. The embryonic fish and early free-swimming
> stages are vertical fish with the eyes on two sides of the body. Later
> development results in the migration of the eyes putting both on the
> same side of the body. The fish now swims on its side and rests
> sideways on the ocean floor.
>> David H. Griffin
> Department of Environmental & Forest Biology
> College of Environmental Science and Forestry
> 350 Illick Hall
> One Forestry Drive
> Syracuse NY 13210-2788
> e-mail: griffin at mailbox.syr.edu
And what of migration of fibroblasts in animal development and wound
repair? How about the complete re-construction of an organisms body form at least
twice in its development (Drosophila). It isn't just fate maps
determined by body location but a lot of cells have to get to the
right spot first and then are affected by morphogen gradients,
neighboring cells, etc.
||Doug Rhoads || Dept. of Biological Sciences||
||drhoads at mercury.uark.edu || 601 Science Engineering ||
||drhoads at uafsysb.uark.edu || University of Arkansas ||
||501-575-3251 || Fayetteville, AR 72701 ||
|| My Dogma Just Got Run Over by Someone's Karma ||