That would make eggs the limiting factor in using nuclear transfer to treat human diseases.
Such nuclear transfer produced Dolly the sheep, the world's first cloned mammal, four years ago.
They were cloned using a double nuclear transfer method similar to the technique used to get Dolly.
The gold standard embryonic stem cells still came from embryos themselves, including ones that were made through nuclear transfer.
Here again, losses occur, and only 10% of the original egg cells used in nuclear transfer make it this far.
Instead, they want to use somatic cell nuclear transfer, the same process used to clone Dolly the sheep in 1997, to create embryonic stem cells.
Nuclear transfer would offer prospective parents a way around the dilemma.
FORBES: UK May Be Close To Approving Nuclear Transfer Technique for IVF
Geron , the stem-cell company he founded before moving to ACT, has often talked of nuclear transfer as a way of figuring out how to make stem cells.
If I understand the tetraploid complementation technique utilized in these experiments correctly, then, scientists would no longer need to generate embryos via somatic cell nuclear transfer (cloning).
FORBES: The Line Between Embryonic And Pluripotent Stem Cell Research Is Blurring
"Nuclear transfer is really about the ability to take an adult cell and basically reprogram it so that you can grow an embryo from it, " Earp says.
The liver is Geron's first target in its plan to use cloning technologies, called nuclear transfer, to produce transplantable cells and organs from the patient's own body.
The problem is that making them using somatic-cell nuclear transfer involves breaking up viable embryos, since the cells in question are found inside early-stage embryos, called blastocysts.
Only last year, she said, Egli and Paull and their colleagues demonstrated that the nuclear transfer of eggs cells could generate patient-specific stem cell lines for potential cell replacement therapy to treat diseases like diabetes.
FORBES: Nuclear Transfer Breakthrough Offers A Way To Prevent Mitochondrial Disorders
Instead of generating embryonic stem cell lines via nuclear transfer, Hwang's group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.
It is a technique called nuclear transfer -- the same used to create Dolly the sheep -- and until Mitalipov's research there had been skepticism over whether a primate could be cloned in the same manner.
Geron (nadsaq: GERN - news - people ), the stem-cell company he founded before moving to ACT, has often talked of nuclear transfer as a way of figuring out how to make stem cells.
In 2001, a gaur nicknamed Noah, a Southeast Asian threatened ox, was successfully created in the womb of Bessie, a cow, by scientists using a nuclear transfer process at Advanced Cell Technology in Massachusetts.
"Somatic cell nuclear transfer does not relate to cloning, and the people who call it therapeutic cloning are creating a lot of confusion, because it is not cloning at all, and it certainly is not reproductive cloning, " Specter said.
In mice, Daley and colleagues have shown that stem cells derived from the nuclear transfer of cells to make embryos -- the technique described in Mitalipov's paper -- were indeed closer to natural embryo stem cells than induced pluripotent stem cells.
Indeed, the same objection also applies to stem cells that are extracted from embryos produced without nuclear transfer. (Usually these are surplus to requirements for in vitro fertilisation.) Both problems would go away if cells that behave like embryonic stem cells could be made without destroying embryos.
Even Dolly the sheep, who was produced by cloning via somatic nuclear cell transfer, benefited from a male imprinted genome.
But why transfer nuclear knowledge to a country that has more than earned its place in President George Bush's axis of evil, ask critics.
ECONOMIST: After yet another naval clash, talks are off, again
And it was therefore reasonable to fear that it would transfer nuclear technology to terrorists who would be only too happy to use it against us.
CENTERFORSECURITYPOLICY: Norman Podhoretz receives the Center's Mightier Pen Award
It pursues a nuclear capability that could spark a dangerous arms race and raise the prospect of a transfer of nuclear know-how to terrorists.
Let me reiterate Pakistan's scrupulous adherence to the policy of non-transfer of nuclear technology or materials to other countries.
There is more reason to worry about the transfer of nuclear materials.
Not surprisingly, the Russian Bear was emboldened to ignore other agreements, especially those concerning the transfer of nuclear technology to Iran.
Relations have improved to the point where they have survived a continuing disagreement about Russia's transfer of nuclear technology to Iran (see article).
"The transfer of nuclear weapons or material by North Korea to states or non-state entities would be considered a grave threat to the United States, and we would hold North Korea fully accountable of the consequences of such action, " Bush said.
应用推荐