Meticulous tests like those done to confirm that disgraced Korean scientists legitimately cloned a dog while faking human data may have to be used to validate scientific claims in the future, U.S. scientists said Tuesday.
A panel at Seoul National University concluded that two reports claiming that human embryos had been cloned to provide stem cells had been completely fabricated, but also found that the same team's claims to have cloned a dog were in fact true.
Dr. Elaine Ostrander of the National Human Genome Research Institute said her team helped confirm that "Snuppy," created last year by Hwang Woo-suk of Seoul National University and colleagues, genetically matched the adult Afghan hound he was cloned from.
"We saw a complete match between the donor Afghan Tai and the putative clone Snuppy," Ostrander told reporters in a telephone briefing.
But it was not a 100 percent match — also evidence that a method called somatic cell nuclear transfer, or SCNT, was used to clone the animal, just as Hwang had claimed, Ostrander said.
In SCNT, the nucleus of the adult cell to be cloned is removed and placed in a hollowed-out egg cell. Chemical or electrical triggers are used to start the egg growing as if it had been fertilized by a sperm.
The resulting animal will carry DNA from the adult cell, but also a tiny amount of DNA, called mitochondrial DNA, from the donor egg. This is what Ostrander's team found with Snuppy.
Ostrander said her team's methods were inexpensive and might become more common after the Hwang scandal.
"In 20-20 hindsight you would say, yes, this sort of validation should be done on this kind of scientific breakthrough," Ostrander said.
"Obviously as a result of this strict interrogation, this is something that will arise," she added.
Science, the journal that published the fabricated papers on embryonic stem cells, said it would withdraw them and would examine how it had been duped.
"I have pointed out in the past that even unusually rigorous peer review of the kind we undertook in this case may fail to detect cases of well-constructed fraud," said Dr. Donald Kennedy, editor in chief of Science.
Experts inside and outside the journal, which is published by the American Association for the Advancement of Science, would be asked what extra safeguards might prevent future scandals, including affidavits from each team member, Kennedy said.
"We are implementing improved methods of detecting image alteration, although it appears improbable that they would have detected problems in this particular case," he said.
Dr. Curt Civin, editor in chief of another journal, Stem Cells, said one of the photographs used in Hwang's Science paper had appeared in his journal in 2003, as part of a paper about human stem cells that had not been created using cloning technology.
"We have asked the authors to explain this," Civin said in a telephone interview. Hwang did not work on the 2003 paper, but members of his team did.
Scientific fraud is rare and the scandal has upset researchers whose field was already under scrutiny because some people oppose doing work with human embryos at all.
"We are all agonizing over this," Civin said. "We always assume a scientist is trying his or her hardest to present the data as truthfully as possible. Now I think every reviewer and every journal is going to look harder at papers," he added.
"In the past, if you made a big claim, you had to have big proof. Now the proof is going to have to be bigger."
Most medical and scientific research is published in journals because of the peer review process. Experts in a field are asked to look at each study, to confirm that it was conducted properly and that the data support the claims.
It is a highly competitive field, with some journals charging subscribers tens of thousands of dollars a year, and with researchers vying to get into the most prestigious publications. Science and Nature, rivals that published the three Hwang papers, are considered among the most prestigious.