( Scientists at Whitehead Institute for B...)Researchers offer proof-of-concept for Altered Nuclear Transfer

The theory, called altered nuclear transfer (ANT), proposes that researchers first create genetically altered embryos that are unable to implant in a uterus, and then extract stem cells from these embryos. Because the embryos cannot implant, they are by definition not "potential" human lives. Some suggest that this would quell the protests of critics who claim that embryonic stem cell research necessitates the destruction of human life. Scientists and ethicists have debated the merits of this approach, but so far it has not been achieved.

"The purpose of our study was to provide a scientific basis for the ethical debate," says Whitehead Member Rudolf Jaenisch, lead author on the paper that will be published in the October 16 online edition of the journal Nature. "Our work is the first proof-of-principle study to show that altered nuclear transfer not only works but is extremely efficient."

First proposed by William Hurlbut, Stanford University professor and member of the President's Council on Bioethics, ANT has been described as an ethical alternative to somatic cell nuclear transfer (SCNT), also known as therapeutic cloning.

For SCNT, a donor nucleus, for example one taken from a skin cell, is implanted into a donor egg cell from which the nucleus had been removed. This egg cell is then tricked into thinking it has been fertilized. That causes it to grow into a blastocyst--a mass of about 100 cells--from which stem cells are removed. These embryonic stem cells can divide and replicate themselves indefinitely, and they can also form any type of tissue in the human body. However, to cull these stem cells, the blastocyst must be destroyed, which some critics insist is tantamount to destroying a human life.

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Source:Whitehead Institute for Biomedical Research