Korean scientists clone 30 human embryos
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《英国医生杂志》
Seattle
South Korean scientists based at the Seoul National University stirred up a storm worldwide last week when they announced in the online edition of the journal Science that they had derived a line of pluripotent embryo stem cells from one of 30 cloned blastocysts created by somatic cell nuclear transfer. In other words, they had created the first human cloned embryos (www.sciencemag.org/cgi/content/abstract/1094515).
Until last week, the consensus among cloning scientists had been that humans—and other primates—might prove much more difficult to clone than mice or sheep.
The team was led by Woo Suk Hwang of the university's veterinary college and Shin Yong Moon, a gynaecologist. Both called for a worldwide ban on human cloning for reproductive purposes. "Our goal is not to clone humans but to understand the causes of disease. Our aspiration is to treat incurable diseases," Dr Hwang told the meeting of the American Association for the Advancement of Science in Seattle. "Now we stop and think before taking the next step."
Woo Suk Hwang: "Now we stop and think before taking the next step"
Credit: AP/ANDY ROGERS
The scientists used 242 eggs from 16 women donors. Because they started with a huge number of eggs, they could vary the methods they used and the media in which they grew the cells. They derived 30 blastocysts and from these tried 20 times to produce a line of embryo stem cells.
The success rate was not high, possibly because of chromosomal abnormalities that appeared in the reprogramming or possibly because of subtle variations in the techniques they used. They ended up with just one line of stem cells, cultivated from a blastocyst that had been cloned from nuclear material taken from cumulus cells belonging to the woman who had donated the egg in the first place. The existence of a dish of embryo stem cells at least in theory opens the way for a kind of "personalised" medicine, in which patients with, for example, diabetes or Parkinson's disease could receive transplants of tissue containing their own DNA, thus sidestepping many of the problems of immune rejection.
But such treatments were in practice years away, acknowledged Donald Kennedy, editor in chief of Science. "Nobody is going to clone any people using this technique. The best hope is that for some people, some women particularly under certain circumstances, it might be a useful way to create a safer form of transplantation therapy. That is about all you can say," he said.
Richard Gardner, who led the Royal Society's working group on stem cells, said: "This announcement does not make attempts at human reproductive cloning any more desirable, ethical, or safe." (See p 415.)(Tim Radford)
South Korean scientists based at the Seoul National University stirred up a storm worldwide last week when they announced in the online edition of the journal Science that they had derived a line of pluripotent embryo stem cells from one of 30 cloned blastocysts created by somatic cell nuclear transfer. In other words, they had created the first human cloned embryos (www.sciencemag.org/cgi/content/abstract/1094515).
Until last week, the consensus among cloning scientists had been that humans—and other primates—might prove much more difficult to clone than mice or sheep.
The team was led by Woo Suk Hwang of the university's veterinary college and Shin Yong Moon, a gynaecologist. Both called for a worldwide ban on human cloning for reproductive purposes. "Our goal is not to clone humans but to understand the causes of disease. Our aspiration is to treat incurable diseases," Dr Hwang told the meeting of the American Association for the Advancement of Science in Seattle. "Now we stop and think before taking the next step."
Woo Suk Hwang: "Now we stop and think before taking the next step"
Credit: AP/ANDY ROGERS
The scientists used 242 eggs from 16 women donors. Because they started with a huge number of eggs, they could vary the methods they used and the media in which they grew the cells. They derived 30 blastocysts and from these tried 20 times to produce a line of embryo stem cells.
The success rate was not high, possibly because of chromosomal abnormalities that appeared in the reprogramming or possibly because of subtle variations in the techniques they used. They ended up with just one line of stem cells, cultivated from a blastocyst that had been cloned from nuclear material taken from cumulus cells belonging to the woman who had donated the egg in the first place. The existence of a dish of embryo stem cells at least in theory opens the way for a kind of "personalised" medicine, in which patients with, for example, diabetes or Parkinson's disease could receive transplants of tissue containing their own DNA, thus sidestepping many of the problems of immune rejection.
But such treatments were in practice years away, acknowledged Donald Kennedy, editor in chief of Science. "Nobody is going to clone any people using this technique. The best hope is that for some people, some women particularly under certain circumstances, it might be a useful way to create a safer form of transplantation therapy. That is about all you can say," he said.
Richard Gardner, who led the Royal Society's working group on stem cells, said: "This announcement does not make attempts at human reproductive cloning any more desirable, ethical, or safe." (See p 415.)(Tim Radford)