Scientific rigour

With the controversy, disappointments and spurious claims that have surrounded SCNT research, the peer review process required nothing less than absolute scientific rigour.

In 2004 South Korean scientist Woo Suk Hwang claimed to have created the world's first cloned human embryos by SCNT, and produced stem cell lines from them. Overnight, Hwang became a national hero, only to retreat in disgrace after confessing his results were fraudulent.

Miodrag Stojkovic's research group at the University of Newcastle in the UK reported in May, 2005, that they had created three cloned blastocysts, but were unable to reproduce an embryonic stem cell line.

In a news article in the January 17 issue of Nature, Stojkovic was quoted as describing the Stemagen advance as "a huge difference" from what his own team had achieved.

Stojkovic, now at the Cellular Reprogramming Laboratory at Prince Felipe Research Centre in Valencia, Spain, is an associate editor of Stem Cells. He congratulated French's team for submitting their blastocysts to genetic analysis, and said there was no doubt that at least one blastocyst was a genuine clone.

But Robert Lanza, from Stemagen's competitor Advanced Cell Technology in Los Angeles, said the article in Stem Cells lacked data needed to confirm the cells were fully reprogrammed to an embryonic state, and that the blastocysts were in good condition.

He observed, from the published photographs of the blastocysts, that they looked "very unhealthy".

French told ALS: "We think the quality of the blastocysts improved each time, and we've had expert advice that the real challenge is to induce a SCNT oocyte to produce a blastocyst - once you're past that stage, it doesn't matter how the blastocyst looks, you have a good chance of getting embryonic stem cells from it."

The five blastocysts were the final yield from 29 experiments over eight months to implant a donor nucleus in surplus, enucleated oocytes obtained from young women between the ages of 20 and 30 after hormonal treatment to induce superovulation.

The Stemagen researchers sacrificed the opportunity to provide ultimate proof-of-concept of one of the most anticipated advances in stem-cell research: isolating embryonic stem cells from the blastocysts and expanding them into self-perpetuating clonal colonies.

French says Stemagen is now working to create more SCNT blastocysts with the aim of isolating and culturing embryonic stem cell lines for research into new therapies for genetic diseases and toxicology screening for new drugs.

None of the techniques his team has used are patentable, so Stemagen plans to capitalise on its success by providing cell lines to other research institutions or companies developing new drugs or therapies for inherited disorders.

"The major benefits we expect will come in the area of using SCNT to create cell lines from individuals with specific inherited disorders," he says.