Word: embryos
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Dates: during 2000-2009
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...hope with hedging. It is the nature of politics to overpromise and mop up later. But the politics of stem-cell science is different. Opponents of ESC research--starting with Bush--argue that you can't destroy life in order to save it; supporters argue that an eight-cell embryo doesn't count as a human life in the first place--not when compared with the life it could help save. Opponents say the promise of embryo research has been oversold, and they point to the cures that have been derived from adult stem cells from bone marrow and umbilical...
...wrote about restoring some motor function and sensation in a few paralyzed patients. At a recent conference of researchers from around the world, a team from Kyoto University in Japan reported success in taking a skin cell, exposing it to four key growth factors and turning it into an embryo-like entity that produced stem cells--all without using an egg. The Kyoto group has submitted its work for publication, after which it will be open to the scrutiny of the scientific community. If successful, it could turn stem-cell science from a tedious, finicky process into a relatively straightforward...
...blueprint of the entire organism--that has been programmed or "differentiated" to be one kind of cell (skin or bone or nerve) and no other kind. Somehow, scientists must trick this mature, fully developed cell into resetting its genetic clock so that it can begin life anew as an embryo...
...first step is to remove the nucleus from an egg and replace it with the nucleus of an adult cell (in Dolly's case, a cell from a ewe's udder). The two components are electrically fused and chemically activated to trick the hybrid cell into dividing like an embryo. Not surprisingly, the process doesn't always go right. "I call it a lottery," says Wilmut. "Even if you use the same method as consistently as you can, you may get some clones with severe abnormalities and some that have only minor ones...
...studies of the faults introduced by reprogramming, Jaenisch, for one, thinks human cloning is now out of the question. "I think we cannot make human reproductive cloning safe," he says. "And it's not a technological issue. It's a biological barrier. The pattern of methylation of a normal embryo cannot be re-created consistently in cloning...