LONDON, March 7: A Chinese scientist claims to have leapt ahead of western scientists by cloning a human embryo in 1999.

Lu Guangxiu, of Xiangya medical college in the southeastern city of Changsha, says she and her team have since grown cloned human embryos to the stage where stem cells could be harvested and then cultured.

Professor Lu’s work, reported in the Wall Street Journal, has not been subject to peer review — the usual form of scientific scrutiny — by scientists outside China. However she has published a paper in a Chinese journal.

Alongside her research, Prof Lu runs an IVF clinic. Access to human embryos and human eggs is a prerequisite of stem cell and cloning research.

Her aim is to use early stage cloned embryos to create a line of embryonic stem cells. These would ultimately be a resource from which to culture spare parts for transplant. The point of cloning in this case — therapeutic cloning, as it is sometimes called — is to avoid rejection of the transplant by cloning the cells from the host’s own body.

Labs around the world have produced human embryonic stem cell lines from surplus IVF embryos, but none has yet cloned a human embryo. Doubts have been thrown on claims to have done so last year by the US firm ACT.

Prof Lu told the Wall Street Journal that her researchers, funded in part by revenue from the IVF clinic and in part by the state, had initially based their cloning on the technique described by Ian Wilmut and colleagues from the Roslin Institute, near Edinburgh, after those scientists cloned Dolly the sheep in 1997. This involves removing the DNA-carrying nucleus of an egg, injecting DNA from an adult cell into the hollowed-out space, and applying a tiny jolt of electricity to fuse cell and nucleus together.

However this method produced few embryos living long enough to grow to blastocysts, the ball of a couple of hundred cells from which stem cells can be harvested.

Prof Lu said that they had achieved more success with a new technique: injecting the donor DNA into the egg, leaving it for a time, and then removing the egg DNA.

As described, however, the procedure remains enormously unreliable and wasteful with donated eggs. Only five per cent of the embryos which were cloned in Prof Lu’s lab develop to the blastocyst stage.

Not only that, the cloned, harvested stem cells die after dividing for a short time, instead of dividing indefinitely.

There is certain to be skepticism outside China about Prof Lu’s claims. But China has been investing heavily in biotechnology for years and has a number of other stem cell research labs.—Dawn/The Guardian News Service.