The swirl around South Korean researcher Hwang Woo Suk is expanding while U.S. Science journal on Thursday announced to launch a review of his earliest achievement.

Hwang's paper, titled "Evidence of a Pluripotent Human Embryonic Stem Cell Line Derived from a Cloned Blastocyst," described how his team harvested human embryonic stem cells from cloned embryos first in the world. The paper was published in the online edition of February, 2004 and in a printed edition a month later.

This paper, while attracting the scientific community and making Hwang a world-class star last year, has aroused more suspicion today when Hwang's other claims are under investigation. Editors of Science journal said they will check the paper more cautiously.

"An earlier paper by Hwang and (his) colleagues attracted much attention as the first demonstration of the derivation of a pluripotent embryonic stem cell line from a cloned human blastocyst," chief editor of the journal, Donald Kennedy, said in a statement.

"Given the concerns raised about the 2005 paper, we are undertaking a careful review of the 2004 paper as well and expect to consult with outside advisors as needed," he said.

In this study, Hwang's team collected tissue cells and eggs from the same donor. Then the researchers drew the nucleus out of the egg and poured the nucleus of the tissue cell in, and cultivated this new egg into an early embryo.

Some researchers now raised the question that Hwang might have faked his "cloned embryos" with embryos developed from one germ cell. Thus the embryos should be like natural twins, but not cloned ones.

Hwang's 2005 paper, also published in Science, described how his team derived 11 embryonic stem cell lines specific for patients with different diseases. This paper is under an official investigation by the Seoul National University in Korea and the Pittsburgh University in the United States.

Earlier this day, Nature, another prestigious scientific journal based in Britain, said it would review Hwang's latest published paper which claimed success of cloning a dog first in the world.

Source: Xinhua