- It will look like any ordinary mouse, but for America's
scientists a tiny animal threatens to ignite a profound ethical
dilemma.
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- In one of the most controversial scientific projects
ever conceived, a group of university researchers in California's Silicon
Valley is preparing to create a mouse whose brain will be composed entirely
of human cells.
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- Researchers at Stanford University have already succeeded
in breeding mice with brains that are one per cent human cells.
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- In the next stage they plan to use stem cells from
aborted
foetuses to create an animal whose brain cells are 100 per cent
human.
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- Prof Irving Weissman, who heads the university's
Institute
of Cancer/Stem Cell Biology, believes that the mice could produce a
breakthrough
in understanding how stem cells might lead to a cure for diseases such
as Parkinson's and Alzheimer's disease.
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- The group is waiting for a key American
government-sponsored
report, due this month, that will decide just how much science can blur
the distinction between man and beast.
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- Last week, however, the university's ethics committee
approved the research, under certain conditions. Prof Henry Greely, the
head of the committee, said: "If the mouse shows human-like
behaviours,
like improved memory or problem-solving, it's time to stop."
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- He accepted that the project might seem "a little
creepy", but insisted: "It's not going to get up and say 'Hi,
I'm Mickey'. Our brains are far more complicated."
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- Biologists know such creatures as "chimeras",
after the mythical Greek monster that was part-lion, part-goat and
part-serpent.
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- Prof Weissman said that there was no way of knowing
whether
the "human-mice" would develop any human characteristics until
after they were born. In previous experiments, pigs with human blood have
been developed at a clinic in Minnesota. Last year, the University of
Nevada
produced sheep whose livers were 80 per cent human and could one day be
used for transplants.
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- An inquiry into laying down rules for research using
stem cells from human embryos was launched last summer by America's
National
Academies of Science. The government-sponsored report, said to be in draft
form, will govern stem cell research in the private sector. It comes at
a time of growing confusion in America over the limits of stem cell
research.
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- President George W Bush halted government-funded research
during his first term of office but several states, including California,
have since passed laws that allow support for stem cell projects from local
taxes.
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- At hearings in Washington last October, Prof Weissman
argued strongly against a ban on "chimera mice". He believes
that the mice would behave like any others, but said that he would monitor
the experiment closely and destroy them at the slightest suggestion of
human-like brain patterns.
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- Supporters of stem cell research at Stanford University
include the actor Michael J Fox, who suffers from Parkinson's disease.
Fox provided the voice for Stuart Little, Hollywood's version of the
"human
mouse'', who talks, has human parents and lives in a New York
apartment.
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- Opponents of Prof Weissman's work accept that his mice
are unlikely to show such obvious human traits, but voice concerns that
the brain cells would begin to organise themselves in a way that was more
human than mouse. There is growing unease over whether human stem cells
could migrate to other parts of the animals, creating human sperm or eggs
in their reproductive systems.
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- Should two such "chimera mice" mate, it could
lead to the nightmarish scenario of a human embryo trapped in a mouse's
womb. William Cheshire, a neurology professor from the Mayo Clinic in
Florida
and a Christian activist, has called for a ban on any research that
destroys
a human embryo to create a new organism.
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- "We must be careful not to violate the integrity
of humanity or of animal life," he said. "Research projects that
create human-animal chimeras risk disturbing fragile ecosystems, endanger
health and affront species integrity."
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- In a recent article for the conservative Weekly Standard
magazine, Wesley Smith, a consultant for the Centre for Bioethics and
Culture
warned that "biotechnology is becoming dangerously close to raging
out of control".
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- He wrote: "Scientists are engaging in increasingly
macabre experiments that threaten to mutate nature and the human
condition."
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- © Copyright of Telegraph Group Limited 2005.
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- http://www.telegraph.co.uk
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