09 février 2005
Le père de Dolly est
autorisé à créer des embryons humains par clonage
Ian Wilmut est le célèbre "créateur"
de la brebis Dolly, premier mammifère né du clonage nucléaire d'une cellule
adulte en 1996. Son laboratoire vient d'obtenir l'autorisation de créer des
embryons humains par clonage à des fins thérapeutiques. Il s'agit en
l'occurrence d'étudier les pathologies des neurones moteurs comme la sclérose
latérale amyotrophique (maladie de Charcot). En association avec Christopher
Shaw (Institut de Psychiatrie, Londres), Wilmut compte prélever des cellules
chez des malades, créer des embryons par clonage, isoler des cellules-souches
chez ces embryons, puis analyser leur développement en neurones moteurs afin de
comprendre quand, comment et pourquoi ce développement devient anormal. En 2004,
les autorités anglaises avaient déjà accordé à un laboratoire universitaire une
semblable autorisation de cloner.
Julia Millington, du groupe
chrétien Prolife Alliance, a vivement réagi à la nouvelle : "Tout clonage humain
est intrinsèquement mauvais et devrait être interdit par la loi". Nul doute que
l'Alliance Kantienne Universelle et son bras séculier (le clone médiatique Axel
Kahn, l'homme qui réussit à être présent sur deux télés et trois radios à la
fois) ne reprendront l'antienne de ce côté-ci de la Manche. Les moralistes
aboient, la science passe.
Quant aux partisans du clonage
reproductif humain, ils ne pourront que se féliciter de la nouvelle. En 2001, la
société Advance Cell Technology (Etats-Unis) avait créé le premier embryon
cloné, mais son développement aberrant fut stoppé à six cellules. En 2004,
l'équipe de Woo Suk Hwang (Corée) avait fait de même en améliorant
considérablement les résultats (six jours de culture, obtention de cellules
pluripotentes). Nul doute que les travaux de Wilmut feront encore progresser la
technique vers plus d'efficacité et de fiabilité. L'argument performatif contre
le clonage reproductif (voyez comme la technique est risquée !) et son
exploitation empathique (voulez-vous créer un monstre ?) ne seront plus demain
qu'un lointain souvenir.
Dolly Scientist Gets Human Cloning
WAGNER, Associated Press Writer
The scientist who attracted the
world's attention by cloning Dolly the Sheep is about to take another major step
for medical research : cloning human embryos and extracting stem cells to unravel
the mysteries of muscle-wasting illnesses like Lou Gehrig's disease.
Ian Wilmut, who led the
team that created Dolly at Scotland's Roslin Institute in 1996, was granted a
cloning license Tuesday by British regulators to study how nerve cells go awry
to cause motor neuron diseases.
The experiments do not involve creating cloned babies, but the
license has nonetheless stirred fresh controversy over the issue and prompted
abortion foes and other biological conservatives to condemn the
supposed to be appeased by Professor Wilmut's declarations that the human
embryos will be destroyed after experimentation and that his team has no
intention of producing cloned babies?" asked Julia Millington of the
London-based ProLife Alliance.
"All human cloning is intrinsically wrong and should be outlawed.
However, the creation of cloned human embryos destined for experimentation and
subsequent destruction is particularly abhorrent."
Wilmut, speaking after the announcement
in Edinburgh, Scotland, defended the move.
"We all take for granted the very much
healthier life that we have now compared with people 100 years ago," he said. "I
think that the majority of people support this type of research and hope it will
be successful in helping to bring useful treatment for diseases like motor
license is the second one approved since Britain became the first country to
legalize research cloning in 2001. The first was granted in August to a team
that hopes to use cloning to create insulin-producing cells for transplant into
In the latest
project, Wilmut and motor neuron expert Christopher Shaw of the Institute of
Psychiatry in London plan to clone cells from patients with the disease, derive
stem cells from the resulting embryo, make them develop into nerve cells and
compare their evolution to that of cells derived from healthy
technique, called cell nuclear replacement, is the same as that used to create
Dolly. It has already been applied to humans by scientists in South Korea
(news - web sites), who created the
clone to extract stem cells.
Dr. Brian Dickie, director of research at the London-based Motor
Neuron Disease Association, said the experiments could revolutionize the future
treatment of motor neuron disease, which afflicts about 350,000 people worldwide
and kills about 100,000 people a year.
"It's about 135 years since (motor neuron
disease) was first characterized and here we are, more than a century later, and
we still don't know the cause of over 95 percent of cases. We haven't got a
diagnostic test for the disease and we've made very modest inroads in slowing
the disease progression," Dickie said.
"This opens up opportunities on three
fronts: to understand how motor neurons become sick and die, to identify genetic
causes of the disease and to rapidly screen new drugs," he said.
The mechanism behind motor neuron disease
is poorly understood because the nerves are inaccessible in the brain and
central nervous system and can only be examined after the patient
disease is an umbrella term for a collection of illnesses of varying severity
that all lead to loss of muscle function because of nerve failure. The most
common is amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's
About 10 percent
of those stricken live for a decade or more, like celebrated physicist Stephen
Hawking. However, most die within five years of the onset of symptoms. Drugs
prolong life by three to six months.
An inherited defect in a single gene is responsible for about 2
percent of cases of the disease. Another 8 percent are caused by some other
unidentified genetic abnormality.
Stem cells are the master cells of the body, appearing when embryos
are just a few days old and developing into every type of cell and tissue in the
body. Scientists hope to be able to extract the stem cells from embryos when
they are in their blank state and direct them to form any desired cell type to
treat diseases ranging from Parkinson's to diabetes.
Combining cloning with stem cell research
will ensure the development of the right kind of cells for study, allowing
scientists to see at which exact point things start to go wrong.
The status of cloning varies widely
across the world, and most countries have no laws or regulation in place. In the
United States, federal government money cannot be used for cloning projects, but
there are no restrictions on privately funded research.
The United Nations (news - web sites) is deadlocked
over the issue and is scheduled to take it up later this month. The United
States and Costa Rica are leading a bid to ban all forms of cloning, while
Belgium is heading a faction that wants to allow it.
Associated Press Medical Writer Emma Ross
contributed to this report from Rome