Schatten quits South Korean ES cell research team

A leading American stem cell researcher has abruptly ended his 20 month long collaboration with the team of South Korean scientists famous for creating the world's first human embryonic stem cell (ES cell) lines from cloned embryos. The same team announced in May that it had managed to derive the world's first ES cells that were genetically matched to injured or sick patients. In August it announced Snuppy, the world's first cloned dog.

Gerald Schatten, from Pittsburgh University in the US, claims that unethical working practices have led him to leave the team. Explaining his decision, Dr Schatten said that he would no longer work with the cloning and ES cell pioneer Professor Woo Suk Hwang, over allegations that his team used eggs taken from a junior scientist in violation of rules meant to prevent coercion of women.

The Seoul National University team, lead by Woo Suk Hwang and Shin Yong Moon, carried out their pioneering work on ES cells using 247 unfertilised eggs donated by 16 women. The researchers needed a large number of donated eggs, since the SCNT procedure - the 'cloning' technology used to create Dolly the sheep, which involves replacing the genetic material of an unfertilised egg cell with that of another adult body cell - is very inefficient. The team, which published its breakthrough in the journal Science early in 2004, created 30 cloned human embryos and derived ES cells from 20 of these, from which they managed to grow one human embryo stem (ES) cell line. But in May 2004, the origin of the 247 donated eggs used came under question. A news report published in the journal Nature claimed that PhD student Ja Min Koo originally said that the donors had included herself and another woman who worked in Hwang's laboratory. But the journal also stated that she later called back, to say she had not donated eggs, 'blaming her poor English for a misunderstanding'.

At the time, Hwang, under pressure to reveal more details about how he recruited enough egg donors for the project, flatly denied the findings, saying that 'Nature's claim is totally groundless', and adding: 'I swear none of my students donated eggs for the research'. Now, Dr Schatten has told the Washington Post that he no longer believes Hwang. 'I now have information that leads me to believe he had misled me', he said, adding 'my trust has been shaken. I am sick at heart. I am not going to be able to collaborate with Woo Suk'.

Responding to Dr Schatten's sudden decision to end their working relationship, Hwang has again stated that his work meets strict government-imposed ethical guidelines, including those governing the donation of human eggs. He told reporters in Seoul that 'I know nothing but Schatten had announced separation', adding 'I will tell everything when the right time comes' before publicly thanking all the women who had given eggs for his projects. A team member said researchers will make an official announcement about their sources of human eggs within two or three days.

Last month Dr Schatten, alongside Hwang and his team, announced the establishment of a 'global hub' for stem-cell storage and research, a not-for-profit collaboration, based in South Korea, which will have satellite human embryo cloning laboratories in the US and the UK. A key member of Hwang's team says that the breakup of the collaboration with the US scientist will not hamper the project. 'Schatten's absence will not bring a problem in the world stem cell bank project', said Ahn Cu-rie, professor of Seoul National University and spokesperson for Hwang, adding 'There are many other scientists in the United States who want to work with us. And the stem cell bank is the only such organisation in the world, so there will be no snag in our research'.