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Proposals for cow-human embryos put on hold

January 11, 2007 By Jim Giles This article courtesy of Nature News.

Chimaera experiments still on the table after authority avoids outright ban.

British plans to create cloned human embryos that contain small amounts of cow DNA have been set back by about a year, after regulators decided to gauge public opinion before granting any licences.

Scientists want to use cow eggs to create and study cloned embryos because human eggs are in desperately short supply. Injecting human DNA into animal eggs, creating a 'chimaera' mix of species, gets around this problem. The work could lead to new treatments for conditions such as Parkinson's disease, and the idea of creating chimaeras for research purposes is relatively uncontroversial among scientists. Researchers elsewhere, such as China, have done work with chimaeric embryos before.

The British government said last December that it was considering banning such experiments, prompting concern among researchers at the University of Newcastle upon Tyne and Kings College London, UK. The two universities submitted an application for a licence to do such work last year.

Such a ban would be a set-back for the UK scientific community, which is currently quite strong in the field of cloning research.

But at the same time, the UK's Human Fertilisation and Embryology Authority (HFEA), the independent body that licenses embryo research, decided to look at the issue. Today, it said that it will consider the applications, but only after a three-month public consultation.

Willing to consider

The Government's white paper policy now has no friends.
Evan Harris
The results will be used to develop a policy for all chimaeric projects, allowing the applications to be considered in the autumn. Applications typically take three months to be processed.

"I'm pleased that it's not an outright ban," says Lyle Armstrong, a member of the Newcastle team. "At least they're prepared to consider following the debate."

The HFEA's consultation is expected to influence the Government's proposal to outlaw the research, which parliament is due to discuss later this year. The HFEA's decision to consider the applications is a boost to politicians who are campaigning for the work to go ahead.

"The HFEA has chosen not to support the Government's ill-thought-through and damaging policy of banning this research, which has been attacked from scientists, patients and ethicists," says Evan Harris, a Liberal Democrat MP. "The Government's white-paper policy now has no friends except those who are opposed to all embryo research."

Switching genes

Armstrong and his colleagues want to insert adult human DNA into a cow egg from which the nucleus has been removed. The resulting embryo would not be completely human, because a small amount of its DNA, less than 0.5%, would come from the mitochondrial DNA that exists outside the cell's nucleus. Such an embryo cannot legally be implanted into a woman and can only be grown for 14 days.

During that two-week period, researchers would study the chemical signals that allow the adult DNA to be reprogrammed into an embryonic form. Some genes that are expressed in adult cells are turned off in the embryo, for example, and the teams want to work out how this switching works.

In the long-term, understanding the process could help scientists to reprogramme adult cells without the use of eggs. That would allow doctors to create new cells to treat conditions in which cell loss is critical. In Parkinson's, for example, neurons are lost from an area of the brain that helps control movement.

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