Caption: Dolly, the world's first clone of adult mammal, was developed by a team of scientists at Roslin Institute at Edinburgh in Scotland. Photo: AP
A study published this week has reawakened debate over the government's need to regulate human cloning, USA Today reports.
In a paper in the journal Cell Stem Cell, researchers took the nucleus of skin cells from 35 and 75 year old men, and produced cloned human embryos. From those they were able to generate embryonic stem cells, valued because they can then be teased into becoming any tissues the body might need, Karen Weintraub writes in the key US newspaper.
The researchers are quick to point out that they would never try to implant that embryo in a woman. Instead, the cells will be used for research purposes with an eye toward developing medical therapies. The promise of stem cells has long been that they could be used to grow tissues the body needs to treat ailments ranging from Parkinson's to spinal cord injuries. Creating stem cells from a cloned embryo presumably would create tissues that wouldn't be rejected by the person who donated skin cells initially, according to the report.
But advocacy groups on opposite ends of the political spectrum said Friday that the study is a reminder of the need for government to step in before someone tries to extend this technique to engineer a human clone.
Animal cloning has been possible since Dolly the sheep was born in 1996, but human cloning has long been considered nearly as impossible as it is unethical. The new paper, which builds on and confirms a study published last year using a similar technique, resolves technical hurdles along the path to human cloning.
"The science is no longer theoretical," said Jeremy Gruber, president of the Council for Responsible Genetics, a New York City-based bioethics organisation.
"We need to start putting laws into place to identify where the line should be drawn in terms of governance of these techniques."
Gruber's organisation, along with the Berkeley, Calif.-based Center for Genetics and Society, both oppose the use of cloning for human reproduction, but support cloning for the purpose of creating embryonic stem cells to be used in research.
The Washington-based Family Research Council, a conservative think tank and lobbying group, opposes all cloning regardless of its purpose. A bill to that effect has been proposed by the current House, but not the Senate, said David Prentice, senior fellow for life sciences at the Family Research Council.
The new study though not aimed at human cloning, makes it more likely that someone else will try to clone a baby, Prentice said. Allowing any cloning, even for research, "allows people to perfect that method so they have good embryonic clones that can be gestated to birth".
Several scientists dismissed that argument, saying that it remains impossible to clone a baby.
"That's just nonsense," said stem cell scientist Rudolf Jaenisch, at the Massachusetts Institute of Technology and the Whitehead Institute. Even in animals, cloning remains challenging, with most clones showing abnormalities and dying early; and human cloning would be far more difficult, he said.
The new paper is more important scientifically than practically, Jaenisch said. The study showed that scientists could reproduce work published last year by researchers in Oregon who used skin cells from a patient to create a cloned embryo and from the cloned embryos derived embryonic stem cells. The fact that cells can be turned into embryonic ones and then made into embryos has been published, Jaenisch said, but it's always useful in science to show that results can be repeated.
Embryonic stem cells created from clones are mainly useful for research purposes, said Robert Lanza, a co-author on the new paper and chief scientific officer at Advanced Cell Technology, a Massachusetts-based biotech company involved in stem cell research and regenerative medicine.
Creating stem cells in this way is too cumbersome to treat vast numbers of patients, he said. Instead, his company and other clinical researchers are looking to help patients through a non-cloning technique that derives stem cells from adult cells. That approach does not involve embryos, has not raised ethical questions and is expected to be far more practical, he said.
Lanza said he believes cloning should be allowed only for creating cells in a dish, not a person.
"The key is not to prevent millions of people from benefiting, but to put in appropriate safeguards so they are not abused," he said.