[cheryl j (OP)]

Sometimes when I read posts that mention colonizing space, I wonder if babies can develop in zero gravity. The only thing I've read is the chicken egg experiment. None of the eggs hatched except, I believe, one that had been pre-incubated for nine days on Earth. What effect does gravity have on chemical reactions, or is the effect probably at a higher level, interfering with tissues and cells making physical contact, and circulation?

[RD]

 [ Invalid Attachment ]
http://actavet.vfu.cz/pdf/199362suppl60017.pdf

The role of gravity in chick embryogenesis

In case of Xenopus oocytes [frog], the gravity appears essential for the determination of the developmental axes, especially for the determination of the dorso-ventral axis ...

In summary, the high mortality of the O-day-old fertilized chick eggs in space appeared to be due to the lack of separation of yolk from albumen in microgravity. In contrast, the high survival rate of the 7- and 10-day-old embryos may have been due to the fact that these embryos were already fixed in the correct position in the egg and angiogenesis had started prior to the time of launch.
The subtle difference in specific gravity between the yolk and albumen plays a critical role in early chick embryogenesis

http://www.sciencedirect.com/science/article/pii/0014579394801681/pdf?md5=632998d25d5a5ff852cbd0becf5b1d1e&pid=1-s2.0-0014579394801681-main.pdf

[CliffordK]

For the control group, the sham launch included shaking, but did not include high G-Force (3G?) acceleration and deceleration (other than jet flight).  Better launch controls are necessary to make a conclusive argument that the developmental problems are due solely to low gravity.

I'm surprised there don't seem to be any mouse breeding experiments on the ISS, although I did find at least one simulated space breeding experiment with damage to the embryos, but some successful implantations.

[cheryl j (OP)]

I really think the effect of gravity on biological processes is interesting, mainly because it's so new, and has always been a factor kind of  taken for granted and therefore ignored. Where can I learn more?

[RD]

... Where can I learn more?

The key search word is "microgravity" rather than "zero gravity" ...
https://www.google.com/search?q=embryogenesis+microgravity

http://www.wired.com/wiredscience/2009/08/spacebabies/

[alancalverd]

It should be possible to replicate the failure by simply rotating eggs slowly in an incubator. This would be a lot more interesting as they could be rotated about one, two or three axes, or randomly tumbled, until we found which direction was critical for development.