Cloned Human Embryos Make Stem Cells
The journal Cell reports that nuclei from adult skin cells were introduced into the nuclei of human egg cells (somatic cell nuclear transfer, SCNT) and they successfully developed as embryonic stem cells. This is a first for human cell technology. If I understand the report correctly, a key step was to transfer the donor nucleus into the oocyte without removing the oocyte nucleus first, because the oocyte nucleus needs to form the spindle structure (the filaments that pull apart chromosomes at meiosis). The original oocyte chromosomes disappear–how that works is unclear to me. But the oocyte divides and forms a seemingly normal blastocyst–early stage embryo.
The achievement brings us a step closer to growing customized organs. The problem with embyronic stem cells has always been that they are specific to a donor, but not to the patient who needs the new organs; now, we see a possible route to solving this problem.
But we also come a step closer to human cloning. Why couldn’t the blastocyst be implanted in a womb and continue embryonic development? Other poorly understood technical problems prevent this, but in principle, such a transformed oocyte could develop into a human being.
Comments are closed.
Ultraphyte 
But they don’t exhibit the same problems as adult stem cells by being highly tumorigenic, do they?
It’s too early to answer that question. We do know that other animals, including sheep, cows, and monkeys, get cloned into normal adults. But each family of mammals has unique challenges in their early development.
It seems clear that cloning will become possible, which leaves the question of how it will be used. Since we have both good and bad in the world, we can assume that it will be used for good (i.e. custom organs) and for bad (i.e. pick a nightmare).
I have read sci-fi books that presupposed both sides, in a variety of imaginings, and the distillation I came away with was this: If we can treat each other inhumanely, there’s no reason to think we will treat clones humanely.
Hello, this really sounds like a breakthrough,
Is the telomeres still shortened corresponsping to the age of the adult skin cells? And does shortend telomeres only matters regarding life expentancy of entities cloned from the cells?
Kind regards
It’s not yet clear about the telomeres, but in other mammals it’s possible to get offspring that live a normal lifespan. In cattle, “nuclear transfer itself may commonly trigger an elongation of telomeres, probably more or less according to donor cell type.”
http://www.ncbi.nlm.nih.gov/pubmed/12021043
The Dolly article on Wikipedia suggests that the cloning procedure itself might have resulted in shortened telomeres. I haven’t seen anything about comparisons of telomere lengths between cloned versus ‘naturally’ produced progeny. (I’ve read that some telomere length variance in human progeny is attributable to father’s age at time of conception – this may also be true among other mammals.)