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Italian, U.S. Scientists Unveil Human Cloning Efforts
Lepruhkawn writes: "As described in this
Yahoo article , scientists say they plan to clone members of infertile couples. I imagine that it's not so much success that people are concerned about as the failed attempts. Alien: Resurrection anyone?"
it turns out human cloning is not possible right now. This is close to my area of research.
What people really mean about 'cloning' is the creation of new organisms that are identical genetically to adults (genetic material from fully differentiated cells). People naturally make clones earlier (twins) and artificially (fertility treatments). The real breakthrough with dolly & such was the ability to take an organism that has developed -- and hence we can observe the phenotype and turn its genotype to a new organism.
ok so along these lines: the initial dolly experiment can about from _hundreds_ of attempts. All the failures either never developed or aborted prematurely. The risks associated from harvesting that many eggs from one human would be high.
Additionally, no one has come close to performing fully differentiated genotype transfer in any higher organism close to man. A science article about a year ago had a good review of what had been tried. Turns out the success rates go dawn sharply as the genome gets more complex.
Finally there is the telomerase issue. We know aging occurs in high correlation with the shortening of end caps on the chromosomes called "telomerases" These shortened telomerases are already present in fully differentiated cells and it was measured in sheep that the cloned animals too have shorter telomerases. The result: there is strong suspicion that cloned animals may have shorter lifespan. Sequential cloning might be disastrous.