castanyes blaves

http://news.bbc.co.uk/1/hi/health/6929203.stm

'Virgin birth'

Researchers said that the distinct "genetic fingerprint" of the stem cells means they may be the first in the world to be extracted from embryos produced by the so-called "virgin birth" method, or parthenogenesis.

This happens when eggs are stimulated into becoming embryos without ever being fertilised by sperm, and has been achieved in animals.

However, before Hwang, no one had managed to produce a human embryo using parthenogenesis which lived long enough to allow the extraction of viable stem cells.

Dr George Daley, who led the analysis, said: "Unfortunately at the time they published their work they did not know what they had done so they had mistakenly isolated these parthenogenic embryonic stem cells, and yet misrepresented them as true clones.

"In fact they had produced the world's first patient-specific embryonic stem cell, and that is very valuable.

"Scientists interested in modelling complex diseases would like to be able to move a patient's own cells into a petri dish in their embryonic form."

'More useful'

Professor Azim Surani, from the University of Cambridge, has carried out years of experiments to produce parthenogenetic stem cells from mice.

He said Hwang had probably inadvertently stimulated the human eggs to begin dividing while trying to produce cloned embryos.

Professor Surani said Hwang's unwitting step forward might actually prove more useful than efforts to clone human embryos, which he had claimed fraudulently.

"I've always promoted the idea that efforts should be made to produce embryos from human eggs - it is far less ethically challenging, and the efficiency of these cell lines is likely to be higher than those produced from cloned embryos," he said.