🚀 go-pugleaf

[About a tongue-in-cheek suggestion for a shuttle experiment funded by
Kentucky Fried Chicken, to study chicken development in space -- actually not
a bad idea, but I doubt Kentucky Fried Chicken would fund it.]

In article <44600021@pyr1.cs.ucl.ac.uk> william@pyr1.cs.ucl.ac.uk writes:
[Last part of the suggestion is >>]
>>   It may also offer clues as to how human embryos may one day
>>develop in space.
>
>Forgive me if I am wrong, (it's a while since I studied the theory!!),
>but are there portions of the human reproductive system that require 
>some sense of orientation prior to fertilisation?  Something to do with
>sperm navigation. [. . .]

	I very much doubt it.  Remember that mammalian females change position
many times between copulation and fertilization, which would really mess up
gravity-dependant sperm.  Also, mammalian eggs do not have the gravity-
sensitive cytoplasmic determinants that amphibian eggs have (or, initially,
any cytoplasmic determinants at all, it seems -- the cells formed by the first
3 divisions seem to be for all practical purposes entirely identical, and can
be rearranged freely without messing up the subsequent embryo).  Note that if
mammalian eggs and embryonic development were gravity-dependant, it would be
very hard to get them to develop properly, again due to the changing position
of mammalian females (yes, vivapary does have its disadvantages).  However,
bird eggs (as well as reptile eggs) are even larger and yolkier than amphibian
eggs, and while it is predicted that the absence of gravity will not disturb
amphibian eggs (or reptile or bird eggs) -- that is, it takes gravity in the
wrong direction and at the right time to mess up development -- the required
data is not yet available.  Experiments to test the development of amphibian
and fish (similar kind of eggs and development) embryos in space are being
designed in the Department of Biology at Indiana University.

	It is my understanding that rats were taken up on one of the Skylab
flights (unless I am getting mixed up and it is the Russians that did this)
and allowed to mate and produce offspring.  The offspring developed completely
normally, and did not even suffer the bone calcium loss that their parents
were experiencing.  Unfortunately, I don't have the reference for this.
Anyone else know of this?

	-- Lucius Chiaraviglio
	   chiaravi@silver.bacs.indiana.edu
	   lucius@tardis.harvard.edu	(in case the first one doesn't work)
	"NO DYING ALLOWED." -- The Maytag coin-operated washing machine
		instruction poster.
	"This would be nice!" -- graffitti seen on the Maytag coin-operated
		washing machine instruction poster in the Daniels laundry
		room in Currier House at Harvard University.