Scientists who created Dolly the sheep, the world’s first cloned animal, said on Wednesday they did not believe South Korean researchers had cloned a human embryo.
“We don’t believe they have provided any evidence that they have achieved what they claimed to have achieved, ” Dr Harry Griffin, of the Roslin Institute in Edinburgh, said in a telephone interview. “The story is grossly overblown.”
Lee Bo-yon and researchers at Kyunghee University Hospital in Seoul said on Wednesday that they had cultivated a human embryo using an unfertilized egg and a somatic cell, those that make up most of the body, donated by a 30-year-old woman.
The Korean researchers said they aborted the experiment after the human embryo divided into four cells.
“If implanted into a uterine wall of a carrier, we can assume that a human child would be formed and that it would have the same gene characteristics as that of the donor,” Lee said.
Technically Possible Somatic cell transfer is the same technique the Roslin scientists used to create Dolly in 1996. Griffin said it was technically possible to clone a human embryo “but this group hasn’t done it.”
Humans start off as a single cell which then divides repeatedly, but it is only after three cell divisions that the nucleus takes over control of the development of the embryo.
“The Korean group stopped the experiment when they saw four cells being produced so there is no evidence that the somatic cell they transferred was reprogrammed,” Griffin said.
He added that he and his colleagues were also puzzled about why Lee went ahead with the experiment now. They said there was no indication that the Korean work was part of a large research program and the South Korean government was considering legislation to control research on human cloning.
Not the First?
Griffin denied that Roslin scientists had already cloned a human embryo.
“There is no substance to the suggestion by Dr Lee Bo-yon that the Roslin Institute has already cloned a human embryo. We have done no research on cloning with human cells. Such research is currently illegal in the UK,” Griffin said in a statement.
Last week a panel of scientists advised Britain to allow the cloning of human embryos to create tissue and organs, but they supported the government’s ban on human reproductive cloning.
If the recommendation is approved by the government, scientists will have to apply for a licence to do the research.
“In the UK an embryo would only be allowed to grow for 14 days. At this stage it would be a small ball of cells barely visible to the naked eye. Implantation of the embryo in the uterus of a woman would not be allowed and neither is it necessary for recovery of human embroynic stem cells,” Griffin said.
Scientists hope that stem cells, which have the potential to be converted to specific cell types, could be used to treat patients suffering from ailments such as Parkinson’s disease, stroke or heart attack. Griffin said it was extremely unlikely that whole organs could ever be grown in the lab.
Dolly was produced by taking the nucleus out of a cell from the mammary gland of an adult animal and fusing it, using an electrical current, into another sheep egg cell from which the nucleus had been transferred.
Since her creation scientists at the University of Hawaii have cloned 50 mice from adult cells and Japanese researchers have produced up to eight calves from a single adult cow.