Chinese scientists have announced that they have created dozens of cloned embryos that are advanced enough for researchers to harvest embryonic stem cells from them. The move, which has been described as a great leap forward in human cloning, will allow researchers to harvest embryonic stem cells (ESC’s) for research as well as providing doctors with genetically identical tissues for transplant patients, thus removing the problems of graft versus host disease.
Lu Guangxiu and her colleagues at the Xiangya Medical College claim to have cloned embryos to the 200 cell “blastocyst” stage – a developmental stage advanced enough to for scientists to harvest ESC’s. According to Guangxiu, 5% of her cloned embryos develop into blastocysts. Her team have also managed to harvest what they believe are ESC’s from the blastocysts and grown them for three generations. However, to convince other scientists that the cells are indeed pluripotent ESC’s capable of maturing into all tissues, Guangxiu will have to carry on growing the cells for many more generations.
This is not the first time human embryos have been cloned. Back in 1998, a group of South Korean researchers reported that they had grown an embryo to the four-cell stage before they destroyed it. Other researchers have attempted to clone human embryos for the purpose of harvesting ESC’s, although their experiments failed as the embryos only divided into a few cells.
The announcement has also added further weight to the concerns of scientists in countries such as the US and the UK who say that their research is being held back by political and ethical concerns. “It takes the air out of the argument that by passing laws here we can stop the technology from moving forward,” says Robert Lanza of US company Advanced Cell Technology.
SOURCE/ REFERENCE: Reported by www.newscientist.com on the 6th March 2002
