New questions about scientific validity are dogging South Korean cloning researcher Woo Suk Hwang and his colleagues. On 4 December, Hwang notified Science editors that a figure in online material that accompanies his group's much heralded 2005 paper on the derivation of embryonic stem (ES) cells from cloned human embryos contained duplicate images. The problem follows close on the heels of Hwang's admission that, despite his previous denials, two members of his lab had donated oocytes for his group's stem cell experiments and other donors had been paid for their donations (Science, 2 December, p. 1402).
Katrina Kelner, Science deputy editor for life sciences, says that it appeared the duplicate panels were not part of the original submission but had been sent in response to a request for high-resolution images after the paper had been reviewed. "From the information that we have so far, it seems that it was an honest mistake," she says. "We have no evidence that there was any intent to deceive."
In May 2005, Hwang and his colleagues reported that it had produced 11 new human embryonic stem (ES) cell lines that carried the genetic signature of patients with diabetes, spinal cord injury, or a genetic blood disorder (Science, 20 May, p. 1096). The paper not only seemed to validate the group's claim a year earlier that it had created a single cell line from a cloned human embryo, but it also reported a huge increase in efficiency for the technique. The figure in question is supposed to show patterns of expression for a range of ES cell markers in the 11 cell lines. But it contains four pairs of apparently duplicated images, even though they are labeled as showing different cell lines.
Gerald Schatten of the University of Pittsburgh in Pennsylvania, who was the corresponding author on the paper and provided the high-resolution images to Science, declined to comment. A university spokeswoman said that the university's office of research integrity had begun an investigation. Schatten and his lab members are cooperating, she said, "and are carefully going through the data we have access to determine how it could have happened."
Rudolf Jaenisch of the Whitehead Institute at the Massachusetts Institute of Technology in Cambridge, says he still has confidence in the reported results. "I believe that this is an extremely important study and I have no reason whatsoever to question any of the published data," he says. Kelner says that Science's inquiries are ongoing and that the journal would issue a correction once the editors were satisfied they understood what had happened.