DNA tests to be performed on Hwang`s stem-cell work

An investigation panel at Seoul National University plans to request DNA tests on the stem cells cloned by Hwang Woo-suk`s team to see whether they are authentic.

Stepping up its probe into Hwang`s research, the independent committee said it will announce its mid-term report tomorrow.

The committee said yesterday that it had seized tissues of teratoma - a final proof of the formation of stem cells - and will ask for the DNA analysis of the tissues in two or three days.

Later in the week, it will also ask for DNA tests on five stem cell lines which Hwang`s team is currently growing. Hwang told a news conference last week that he can prove the authenticity of his research with the stem cells being cultivated.

DNA tests are the key to proving whether the purported patient-tailored stem cells are indeed created by cloning patients` cells, not from embryos at a fertility clinic.

DNA tests produce peak readings that are then compared to determine their similarity.

When the position of peaks in fingerprint trace of stem cells is identical to the one of the original somatic cells, they are considered to be derived from the same person.

But in each experiment, a fingerprint trace has peaks of different heights, alignment and background noises.

Hwang`s critics said the independent traces are strikingly similar, not only in terms of the position of peaks, but also in other properties, suggesting that they are traces of the same cells, not from two independent ones.

The SNU panel, consisting of seven SNU faculty members and two outside experts, sealed off Hwang`s office on Monday, analyzed records of experiments and interviewed 24 team members.

It said yesterday that it had seized materials on the use of human eggs from September to November. The number of ova used for Hwang`s landmark research is among a series of controversies involving Hwang`s work.

Roh Sung-il, the co-author of the paper who provided human eggs from his fertility clinic for Hwang`s research, said at a news conference yesterday that he had supplied 900 ova to him, whereas claims in his paper that a total of 185 ova were used in the research.

Hwang and his team claim to have raised the success rate of extracting cloned stem cells by deriving 11 stem cells from 185 ova in his 2005 paper. In his 2004 paper, he produced only one cloned stem cell from 242 human eggs.

Therefore, Roh raised suspicions that the actual number of ova used for the research exceeds 185, and have called for Hwang`s team to reveal where the rest of the ova were used.

Key questions on his work, among other suspicions, are how many patient-specific stem cells Hwang`s team has inflated for Science paper and whether the landmark stem cells existed at all.

Hwang already admitted at a news conference that 3 out of the 11 cells were established after his paper was accepted on March 15, suggesting that he inflated the number of stem cells.

However, Korean scientists said the cells did not exist at all, citing redundant photographs and DNA fingerprints of the stem cells published alongside the paper.

Hwang also admitted that there were "artificial mistakes" and "decisive mistakes" in producing stem-cell photographs, saying that he would retract them from the paper.

But, he claimed that his team had established 11 patient-tailored cells, saying his five fellow researchers have witnessed the whole process.

In May, Hwang`s team announced that it did produce 11 different embryos from the cells of patients and then cultivated stem cell lines from them.

The stem cells can be grown into healthy tissue to replace those in people with intractable illnesses, increasing hopes for developing treatments for hard-to-cure diseases.

(hjjin@heraldm.com)





By Jin Hyun-joo