Discussion opener for GRGR(9)

[Paul Mackin]

17) `the best theory of how is Rollo's' (147.26). Anyone know enough
     physiology to validate the melanocyte-CNS link?


Even though Rollo's link between the skin and
the central nervous system is MADE UP, one would
be very surprised if there weren't some small grain
of scientific knowledge lurking somewhere. Can't
resist mentioning the little I'm aware of, even though
probably there are physiologists, neurologists, 
embryologists, or other assorted bio-medical types out
there in p-list land.

 It's not only the fact that cell differentiation,
 specialization into different kinds of tissue, and eventual
migration throughout the body obviously DO 
occur, but the CNS (brain and spinal chord) IS
(strange but true) derived from the same fundamental
kind of tissue as the skin, unlike muscle tissue,
for example, which is different in origin.
Moreover, dedifferentiation and redifferentiation
are probably not unheard of, though certainly they
don't extend to the type of role reversing and
exchange imagined by good old Rollo.

These possibilities of interchangeablity are mostly I
think at the EMBRYONIC stage. So the author is making
another really giant leap in extending them to Gavin Trefoil's
post-partum life cycle. Is Rollo saying not only
that embryonic development of the individual goes
through similar steps to those experienced by the
species in its evolution (ontogeny recapitulates
phylogeny or however it goes), but there also can occur
during post-embryonic life things similar to what went
on embryonically. This possiblity would mean that
the encoded information in the genes of the chromosomes
would have to be extended but at this point THAT would
be a mere detail.


Anyway . . .

				P.