Embryo clones of two men made from skin cells
Pastor Dale Morgan
Embryo clones of two men made from skin cells*
By Malcolm Ritter, Associated Press
NEW YORK — Scientists in California say they have produced embryos that
are clones of two men, a potential step toward developing scientifically
valuable stem cells.
The new report documents embryos made with ordinary skin cells. But it's
not the first time human cloned embryos have been made. In 2005, for
example, scientists in Britain reported using embryonic stem cells to
produce a cloned embryo. It matured enough to produce stem cells, but
none were extracted.
Stem cells weren't produced by the new embryos either, and because of
that, experts reacted coolly to the research.
"I found it difficult to determine what was substantially new," said
Doug Melton of the Harvard Stem Cell Institute. He said the "next big
advance will be to create a human embryonic stem cell line" from cloned
embryos. "This has yet to be achieved."
Dr. George Daley of the Harvard institute and Children's Hospital Boston
called the new report interesting but agreed that "the real splash" will
be when somebody creates stem cell lines from cloned human embryos.
"It's only a matter of time before some group succeeds," Daley said.
Korean scientist Hwang Woo-suk claimed a few years ago that he'd created
such cell lines, but that turned out to be a fraud.
Dr. Samuel Wood, a co-author of the new paper and chief executive of
Stemagen Corp. of La Jolla, Calif., said he and his colleagues are now
attempting to produce stem cell lines from the embryos.
The work was published online Thursday by the journal Stem Cells.
Scientists say stem cells from cloned embryos could provide a valuable
tool for studying diseases, screening drugs and, perhaps someday,
creating transplant material to treat conditions like diabetes and
Parkinson's disease.
But critics raise objections. The process "involves creating human lives
in the laboratory solely to destroy them for alleged benefit to others,"
said Richard Doerflinger, spokesman for the U.S. Conference of Catholic
Bishops.
Citing the earlier work in Britain, he also said that as a scientific
advancement, the new work was "very limited."
Other objections to cloning include concerns about health risks and
exploitation if large numbers of women are asked to provide eggs.
Those objections are one reason that an alternative route to stem cells
made headlines last November. Scientists reported a relatively simple
way to turn skin cells directly into stem cells. This direct
reprogramming carries a theoretical risk of cancer for the recipients of
tissue from these cells, however, and many scientists have urged that
work continue on the cloning technique as well.
The cloning approach involves inserting DNA from a person into an egg,
and then growing the egg into an embryo about five days old before
extracting the stem cells. At that stage, the embryo is a sphere of
about 150 cells.
In the new work, researchers took skin cells from Wood and another
volunteer and produced three embryos with DNA matching the men's.
Further DNA testing on one of these embryos strengthened the case that
it was a clone, researchers said.