BioEd Online

After declaring last week that he had successfully used genetic material from dead people in cloning experiments, fertility researcher Panayiotis Zavos has had a peer-reviewed paper on human cloning pulled by the journal that accepted it.

Zavos has made several cloning claims in recent years, including an assertion that he had implanted a cloned human embryo into a woman. But he has yet to support any of his claims with published work.

On 30 August, Zavos told a London press conference that he had created cloned human embryos by mixing genetic material from dead people with cow eggs. He claimed that the supporting data was in the press with a peer-reviewed journal, which he did not name.

On his website, Zavos lists a paper about the use of cow eggs for human cloning as 'in press' with the Journal of Assisted Reproduction and Genetics. But the journal's editor-in-chief, Norbert Gleicher, says that the paper, which had been scheduled for publication, has now been withdrawn. "We do not tolerate unauthorized prepublication publicity," he says.

Gleicher would not disclose details of the paper, but says that he was also concerned by Zavos's public portrayal of the work. "Nothing in the paper we initially accepted had anything to do with cells from deceased individuals," he told news@nature.com.

DNA from the dead

Zavos claims to have experimented on DNA from three donors: an 18-month-old boy who died after surgery, an 11-year-old girl who was killed in a car crash, and a 33-year-old man who died in a road accident.

The claim has sparked worries that cloning might be seen by some as a way to bring back the deceased.

"It is grossly misleading to suggest you can replicate a loved one by producing a cloned person with the same genetic material," says Richard Gardner, who chairs the Royal Society's working group on stem-cell research and cloning.

Zavos says that he took money from the children's parents to fund his research, but denies that he was exploiting their desperation.

According to Zavos, he fused the donor cells with cow eggs, which are easier to obtain than human eggs, and allowed them to develop for a short period of time. One embryo divided into a ball of around 64 cells before it was destroyed. This is a big step towards reproductive cloning, he claims.

Rabbit technique

Similar methods have been tried and tested before, albeit with a different purpose. Last year, Huizhen Sheng from China's Shanghai Second Medical University and colleagues isolated stem cells from cloned human embryos that had been made by fusing adult human cells with rabbit egg cells. Their results were published in Cell Research.

The team hopes its technique will pave the way for therapeutic cloning, which could help scientists develop donor-matched replacement tissues for diseases such as diabetes and stroke. Unlike Zavos, they are not interested in cloning individuals.

Both types of cloning are up for discussion at a United Nations meeting scheduled for October. Although the United States is pressing for a ban on all forms of human cloning, many scientists are keen to confine any veto to reproductive cloning alone.