How
cloning stacks up
Posted 7/12/2006 7:02 PM ET
By Gregory M. Lamb,
The Christian Science Monitor
Ten years ago this month, a ewe at a quiet research facility just
outside Edinburgh, Scotland, gave birth to a lamb, known then as 6LL3.
Seven months later, 6LL3 stepped onto the international stage with a
more personable name as the most famous sheep of all time: Dolly, the
first cloned mammal. She was the product of inserting a cell from an
adult sheep's udder into a sheep egg from which the nucleus had been
removed, then placing it in a ewe to develop.
Dolly changed the public's idea of what biotechnology might do and
immediately posed the question: Can human clones be far behind?
LOOKING BACK: Dolly was world's hello to cloning's possibilities
"Dolly was important as a symbol of science gone out of control," says
Arthur Caplan, director of the Center for Bioethics at the University
of Pennsylvania. "People were very afraid of cloning and what it might
mean in terms of genetic engineering."
A decade later, those concerns and speculations have cooled. Cloning,
it turns out, is a difficult proposition. Dolly was the sole survivor
among 277 attempts to clone a sheep. Human cloning has proved elusive.
Progress in cloning for research and medical purposes was hit hard late
last year when an apparent breakthrough by South Korean researcher
Hwang Woo-Suk, who claimed to have created human embryonic stem cells
through cloning, was exposed as a fraud.
Cloning to reproduce a human being is now seen almost universally as
too dangerous to consider. And animal cloning hasn't attained many of
the goals expected a decade ago. Still, at least 15 mammals have been
cloned (though no primates) and research continues.
What will the next 10 years bring? Here's what several close observers
say:
Human reproductive cloning still unlikely
"We spent an inordinate amount of time" arguing over human reproductive
cloning 10 years ago, but "I don't think that's going to wind up being
a very important issue 10 years from now." Dr. Caplan says. "I think
the last 10 years have shown that cloning is a difficult process to
control, often goes wrong, and that many of the reasons it goes wrong
are probably inextricably tied up to the cloning process itself. I
think that will pretty well seal the fate of cloning to make human
beings. It will be understood that the price will be too high."
In a 2001 paper in the journal Science, Ian Wilmut, the lead researcher
on the Dolly project, and Rudolf Jaenisch, a biologist and biomedical
researcher at the Massachusetts Institute of Technology, wrote that
human reproductive cloning was inherently dangerous and would always
leave deformities in the clones.
"You cannot make normal clones. The ones that survive will just be less
abnormal than the ones that die early," Dr. Jaenisch says today. "There
has been no progress — none — in the last six years in making cloning
more safe." For human reproduction, cloning "is totally out of the
question."
Some 50 countries (though not the United States) have passed laws or
issued regulations against cloning to make humans. That reproductive
cloning is so widely condemned "even if only on narrow safety grounds"
shows that "some lines can be drawn" past which science won't go, says
Marcy Darnovsky, associate executive director of the Center for
Genetics and Society in Oakland, a non-profit interested in the public
policy implications of genetic manipulation.
Battle over therapeutic cloning
The goal of cloning early-stage human embryos to produce stem cells for
use in research, and eventually to treat diseases, is likely to remain
controversial. Those who see this research as destroying human life and
those who do not regard these blastocysts (embryos in their very early
stages) as human life have found little middle ground.
The battle is between "those who see this as the first step to a Brave
New World and those of us who see this as a legitimate ... step toward
regenerative medicine and all the benefits that can accrue" from that,
says James Hughes, a sociologist and executive director of the
Institute for Ethics and Emerging Technologies in Hartford, Conn. The
group promotes the use of biotechnology to expand human capacities.
Bioethicist Caplan expects that one or more groups of scientists,
perhaps outside the US, will do "what the Koreans said they did" and
clone human stem cells. They'll be "useful in the laboratory, but we
still won't be in a position to see cures coming from cloned human stem
cell lines" in the next decade, he predicts.
Widespread cloning of human stem cells would create a huge demand for
women's eggs and in turn create an ethical challenge, Ms. Darnovsky
says. The health effects on women who donate their eggs are not well
studied or well understood, but early research indicates they could be
taking serious risks. How can women give their informed consent to
providing eggs, she says, if the risks are unknown? Paying women to
provide eggs might induce poor women to put themselves at risk for the
money.
"We don't want to go down the road of a market for eggs," she says.
Beyond that, she worries that human cloning research will have a
spinoff or "dual use" effect. By combining cloning technology with
other genetic manipulation, it may be possible to produce enhanced
"designer babies."
Dr. Wilmut and others see this as a welcome way to improve progeny and
prevent inherited diseases.
Darnovsky disagrees. "That's a disturbing development," she says. "The
procedures that would allow enhancing future generations are ... the
hydrogen bomb of this whole set of human biotechnologies." Not the
least of the concerns would be the potential social inequalities
between "unenhanced" children born to the poor and those born to
wealthy parents, who could afford to select the traits of their future
children.
Animal clones: cattle, pigs, pets
The cloning of pets is controversial, too. Physical appearance can vary
slightly from the original, and it's unclear if the disposition of Fido
or Fluffy will be reproduced in the copy.
Farm animals are another matter. The Food and Drug Administration (FDA)
is expected to issue a risk-assessment soon on the safety of milk and
meat from the progeny of cloned animals. Mark Walton, president of
ViaGen, an animal-cloning company in Austin, Texas, is sure the
offspring of clones will be found to be completely healthy and their
meat and milk products identical to those from non-cloned sources. "We
anticipate that cloning will be accepted as a standard technology" used
to breed farm animals, Mr. Walton says.
Cloned animals will not be slaughtered for meat or give milk. They're
far too valuable for that. They will be used only for breeding, Walton
says. It is only their offspring born through traditional breeding
techniques that will be consumed. Following the expected FDA approval,
he says, in the next decade some 30 to 50% of breeding boars may be
clones, selected for their superior traits, meaning that 30 to 50% of
the pork on the market would come from their progeny. Perhaps 10 to 20%
of breeding bulls could be replaced by clones as well, he says.
The question of defective clones is less crucial in farm animals, since
any defects would not be passed to future generations, Walton says.
The assertion by Wilmut and Jaenisch that all clones will be defective
is "wrong," Walton says, calling it an "oversimplification." "Will
there be clones that are born that aren't healthy clones? Absolutely,"
he says. But that's true of naturally born animals too. "That's just
part of life," he says.