Scientists claim world cloning first

Cloning could produce perfect-match tissue for transplant

Australian scientists have claimed a world first by demonstrating in a mouse nearly all the major technical steps of so-called therapeutic cloning.

This technology, which involves the creation of embryos to "harvest" special cells, has the potential to revolutionise the treatment of degenerative diseases such as Alzheimer's and Parkinson's.

The application of this limited form of cloning to humans, however, is highly controversial and opposed by several church and anti-abortion groups.

But Professor Alan Trounson, from the Monash Institute of Reproduction and Development, Melbourne, said his organisation had shown that therapeutic cloning was no longer a concept in need of proof.

"We have shown that in a mouse, this model will work," he said. "It is no longer just a hypothetical - it is a reality. And if we did the same type of work in a human we would expect the same outcome."

Desired tissue

Monash PhD student Megan Munsie took the genetic material of a mouse and fused it with an empty egg cell, using the cloning technique pioneered by the Scottish scientists who created Dolly the sheep.

The resulting embryo clone was then mined for the special "master cells" that have the potential to develop into almost any kind of tissue in the body.

Scientists believe that if they can control the direction of these embryonic (ES) stem cells they can "grow to order" any desired tissue for transplant.

Using a cloning step not only provides access to these special cells but ensures any resulting tissue will be a perfect match for the patient and will not be rejected by the immune system.

Munsie has demonstrated this to be the case by transplanting the mouse ES cells back into the original rodent with no ill effects.

The one major step of therapeutic cloning not completed in this research was to direct the ES cells into one specific cell type.

But the Monash group now intend to refine the work to create nerve cells suitable for repairing the damaged brains of mice with neurodegenerative conditions similar to Alzheimer's and Parkinson's disease in humans.

Ethical objections

Any form of human cloning is banned in Australia, as it is in all of the major, western, industrial nations.

However, an Australian House of Representatives committee is currently reviewing the merits and ethics of the various techniques involved in therapeutic cloning.

Professor Trounson said no-one wanted to see humans copied to make babies, but argued that a more limited use of the emerging cell technologies should be permitted under strict guidelines.

"These techniques have an enormous potential in cell therapy for almost any neurodegenerative disease, as well as other conditions such as spinal injury, diabetes, and coronary heart disease," he told BBC News Online. "Worldwide research has now got to find out if that potential can be realised."

An expert panel in the UK is expected to give a cautious go-ahead to therapeutic cloning when it publishes a nine-month review of the issues surrounding the research on Wednesday.

Some scientists in the UK have threatened to leave for foreign labs if they are not allowed to pursue therapeutic cloning research.

However, groups such as the Catholic Church have condemned any practice which creates embryos merely to discard them after harvesting some useful cells.

Other opponents believe therapeutic cloning would inevitably lead to individuals, particularly infertile couples, demanding that the law be extended to allow people to copy themselves as a way of having children.

The Monash research is published in the international journal Current Biology. The work was carried out in collaboration with Stem Cell Sciences, an Australian biotechnology company.

Megan Munsie and co-author Peter Mountford