Boston: Astudy that appeared to have important implications for embryonic stem cell research was retracted from the journal Science after scientists found that photos in it had been faked.

A probe by the University of Missouri at Columbia found that the paper’s first author, Kaushik Deb, doctored images from one cell to make it appear they had come from several different cells, said R. Michael Roberts, an animal science professor and Deb’s supervisor, in a letter to the journal.

Science said in October that Deb’s results, published in February 2006, might not be reliable, and it waited for the author’s retraction after the university finished investigating. Science, Nature and other journals have been on guard against retouched pictures since the faked stem cell results of South Korean scientist Hwang Woo Suk were exposed last year.

“Ultimately, we do see this as part of the self-correcting process of Science,” said Ginger Pinholster, a spokeswoman for Science, in a telephone interview. “The big picture is that Science publishes about 950 research articles a year and we end up clarifying or retracting only a handful, and that figure has not increased particularly.”

Deb was studying which embryonic cells become stem cells and which implant the embryo into the placenta. His studies suggested that a protein, called cdx2, marked cells involved in implantation, suggesting that unmarked cells might be fated to become stem cells.

Other scientists, wary of doctored images after Hwang’s fakery, scrutinized the work closely and determined that a series of photos had been altered to look as though they had come from distinct cells, Roberts said.

Three other papers that described cellular molecules called transporters were retracted from Science in December after the lead authordiscovered he had mistakenly flipped images of themolecules.

Roberts said he didn’t expect to have to ferret out fraud while he was overseeing Deb’s work.

“He was relatively independent; I never looked over his shoulder,” Roberts said in a telephone interview. “Science is based on trust. If you’re going to mentor people, it’s almost impossible to look over their shoulders the whole time.”

Other scientists involved in the study have been cleared of blame by the investigation. Roberts and his colleagues are trying to determine whether there was any shred of truth to the findings.

Deb has resigned from the university, and Roberts said he believes the young scientist has returned to his home in India. Deb hasn’t returned telephone calls, letters or emails, Roberts said.

“You really do tend to look at yourself and say ‘How did this get past me?”’ he said. “You have to scrutinize everything without being paranoid.”