X-Message-Number: 7466 From: (Steven Haywood) Date: 09 Jan 97 02:58:00 -0800 Subject: Cloning Reply-To: Subject: Cloning In message #7338, Brian Wowk wrote the following: >anywhere near as bad as hamburger), but the technology for >turning hamburger back into cows has existed for years. Furthermore, >the technology for doing so is highly suggestive of the kind of future >technology that might allow revival of cryonics patients. >So (to prove that the average sci.cryonics reader is >more imaginative than the average cryobiologist) can anyone guess >how to turn hamburger back into a cow with existing technology? In message #7341, Will Dye wrote the following: >Well, I suppose you could mix the hamburger into the >feed of another cow, and thus recycle many of the >original atoms. You could also produce (through >various techniques) a cow that has much or most of >the original cow's DNA, thus preserving an important >pattern that was in the original cow's atoms. Few cells in animals are totipotent, past the early embryo stage. In most adult animals, even the most versatile cells are only pluripotent, which means that although they can give rise to more than one kind of cell, they can give rise only to a few kinds. But most mammalian cells either do not divide at all after a certain age or else can divide only to produce replicas of themselves. Although every nucleated cell of the body contains a copy of the entire genome, only small clones of mammals can be produced--by splitting early embryos. Successful somatic cloning would require us to de-differentiate already differentiated DNA. One form of somatic cloning is already becoming possible by culturing embryonic tissue, before the DNA is irrevocably switched off. Some agricultural research is already aiming to multiply "elite" livestock in just this way. Whatever can be done with cattle can almost certainly be done with human beings. The embryonic tissue route to human cloning should, in short, be technically feasible within a few decades. Steven Haywood --- * Alley Drive Software, Maple Ridge, BC, Canada 604-463-1776 (1:153/265) * Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7466