THE cloning scientist accused of faking his pioneering embryonic stem (ES) cell research stood by his work yesterday, even as he asked a journal to withdraw a paper after admitting that it contained serious errors. Woo Suk Hwang confirmed that he wanted to rescind a study claiming the creation of the first cloned ES cells tailor-made to match individual patients, which was published to world acclaim in May in the journal Science.

While he denied allegations by a senior colleague that results presented in the study were fabricated, the scientist, from Seoul National University, in South Korea, accepted that it included “fatal errors and loopholes” and apologised for the mistakes.

Professor Hwang said that he had been surprised and embarrassed at the charges made by Sung Il Roh, a co-author, who asserted on Thursday that most of the colonies of ES cells featured in the study had not been authentic clones.

“Of the eleven stem cell lines, at least nine are faked, and the veracity of the two others has yet to be confirmed,” Dr Roh said, adding that Professor Hwang had admitted this to him privately.

Professor Hwang rejected this yesterday, saying that although six of the lines had died of a fungal infection, five were still frozen and would be thawed and reanalysed to vindicate his work.

“Our six research members made eleven stem cells and all confirmed this,” he said. “What I can say clearly is that we have produced patient-specific stem cells and we have the technology to do so.”

He confirmed, however, that he wished to retract the Science paper because of “irretrievable mistakes in the photography” that accompanied the results.

The Korean team had already admitted that several of the images of stem cell lines published in the journal were duplicates.

His decision to withdraw the paper has baffled independent experts, who said that the photographic errors were not sufficient to overturn the rest of the paper’s data. Stephen Minger, a professor at King’s College London, said: “There is something very odd going on here that doesn’t make sense to me. Hwang has to try to clear his name, and the only way to do this is an independent investigation.”

Professor Hwang’s team has been the world leader in stem cell science since it announced the first cloned human embryo last year.

The disputed Science paper purported to show the first ES cells cloned from people with conditions such as Parkinson’s disease and diabetes. Such cells could potentially be transplanted into these patients to replace diseased tissue without risk of rejection.

Doubts about the research surfaced last month, when it emerged that Professor Hwang had used eggs donated by researchers in his laboratory. The scandal led Professor Hwang to resign from an international cloning consortium.

Gerald Schatten, of the University of Pittsburgh, who ended a long research partnership with Professor Hwang over the egg scandal, asked Science to withdraw his name from the paper this week.

A spokeswoman for Science confirmed yesterday that Professor Hwang and Professor Schatten had contacted the journal to retract the paper, and that its editors would comply provided that all the authors consented.

Seoul National University has begun an inquiry into Professor Hwang’s research.

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