Major developments of controversy surrounding Hwang Woo-suk's stem cell research

Following is the chronology of major developments of the controversy surrounding research work of the embattled Hwang, which shocked the country.

February 2004 -- U.S. based journal of Science published a paper of Hwang's team, which says it succeeded in producing the world's first human embryonic stem cells from cloned human embryos.

May 2004 -- Another renowned journal, British-based Nature, cast doubt on the ova procurement process in Hwang's research, hinting two junior female researchers donated their eggs. Hwang denied the report.

May 2005 -- Science published a cover story on Hwang's team's new claim that they had successfully cloned 11 different stem cells tailored to individual patients for the first time in the world. The development was widely highly praised as it paved the way for finding new ways to treat hard-to-cure diseases.

June 2005 -- An investigative reporting program of MBC, one of the three major broadcasters in South Korea, received a tip that Hwang's team had violated ethics codes in research and his 2005 paper in Science is fraudulent. "PD Notebook," the MBC's investigative program, started its own probing over the tip.

August 2005 -- Hwang's team held press conference to show " Snuppy,"-- the world's first cloned dog, to media. Its paper on the cloned dog also was published in Nature in that month.

October 2005 -- The SNU, where Hwang is a professor, launches the World Stem Cell Hub. Hwang became head of the hub.

Nov. 13, 2005 -- Gerald Schatten, a U.S. professor at the University of Pittsburgh and a partner in Hwang's research, said in a statement he stopped cooperation with Hwang due to suspicions of unethical problems in Hwang's research.

Nov. 22, 2005 -- "PD Notebook" broadcasted a program that included strong evidence that Hwang's team used ova extracted from its junior researchers.

Nov. 24, 2005 -- Hwang held a press conference, admitting ethical lapses existed in his research and announcing resignation from head of the World Stem Cell Hub.

Dec. 4, 2005 -- After broadcasted another program of challenging the authenticity of Hwang's 2005 paper published in Science, MBC suddenly made a public apology for some of its producers violated journalistic ethics in covering the story.

Dec. 11, 2005 -- Hwang's research team asks Seoul National University to re-examine its 2005 paper on individual-specific stem cells.

Dec. 15, 2005 -- Roh Sung-il, an administrator at the MizMedi Hospital and a collaborator in Hwang's research, said he was told by Hwang that there are no individual-specific stem cells as claimed in the 2005 Science paper.

Dec. 16, 2005 -- Hwang held a press conference, admitting partial images of the stem cell lines were manipulated in the 2005 Science's paper.

However, he argued his team does have "source technology" of producing patient-tailored stem cells.

Dec. 18, 2005 -- SNU launched a nine-member panel to probe into Hwang's research.

Dec. 23, 2005 -- The SNU ad hoc panel said in its initial report that the production of nine patient-tailored stem cell lines was a fabrication. At the same day, Hwang offered resignation of his professorship of the SNU.

Dec. 29, 2005 -- The SNU panel concluded in its second report that DNA tests have shown that no patient-tailored embryonic stem cell lines exist currently. It also said it did not find any evidence Hwang's team had successfully cultivated such patient- tailored stem cells.