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World’s
first cloned animal
passes into immortality
Dolly,
the most famous sheep in the world, has been put down because
of lung disease. "We are sorry to report that Dolly the sheep
is dead," the Roslin Institute in Scotland announced last
week.
Dolly made history when she became the first animal to be cloned
from an adult cell. The prestigious journal Science declared the
Finn Dorset sheep the scientific breakthrough of 1997.
Her cloning, which paved the way to unprecedented genetic manipulation
of farmyard animals, also triggered much soul searching.
Then US President Bill Clinton set up a commission to ask what
the implications of the "startling news" were for people.
Prof Richard Gardner, chairman of the Royal Society working group
on therapeutic cloning, said: "We must await the results
of the post-mortem on Dolly in order to assess whether her relatively
premature death was connected with the fact that she was a clone.
"If there is a link, it will provide further evidence of
the dangers inherent in reproductive cloning and the irresponsibility
of anybody who is trying to extend such work to humans."
Dolly came to enjoy a celebrity lifestyle, albeit one confined
to Roslin. As an experimental animal, she was banned from opening
fetes or attending agricultural shows.
She was interviewed by the author Fay Weldon, posed with a Japanese
couple for wedding photographs and was fleeced in the name of
medical research. The sweater produced from her wool is in the
Science Museum.
The Roslin said the decision was taken to "euthanase"
six-year-old Dolly by injection after an examination showed progressive
lung disease.
Dr Harry Griffin said: "Sheep can live to 11 or 12 years
of age and lung infections are common in older sheep, particularly
those housed inside. A full post-mortem is being conducted and
we will report any significant findings."
One of the key unanswered questions about Dolly is her true "genetic"
age. Although she was born on July 5 1996, all the cells in her
body sprang from a single cell in a six-year-old ewe. Some would
argue that her age at death and the age of the ewe would make
her 12.
In 1999, researchers found evidence that Dolly might have aged
prematurely and two years later she developed arthritis in a hind
leg and hip.
Arthritis in sheep is quite common, but it is comparatively unusual
for it to be in these joints. Prof Ian Wilmut, who led the team
that created Dolly, said the ailment was likely to be linked to
the "inefficient" cloning process. Prof Wilmut said
the early indications were that Dolly, cloned from a breast cell
and named after the singer Dolly Parton, had contracted the disease
from other animals in a shared pen.
"There is always a greater risk if you have animals inside
that infections will spread, so we had been concerned about this.
It's a very slow, progressive illness but we won't know the details
until a post mortem examination has been completed."
The institute plans to publish any "significant post mortem
results" amid fears that the sheep's death was linked to
premature ageing.
"The elbow is the most commonly affected joint," said
Tim King, the veterinary surgeon on the project. In all other
ways Dolly was in good health and she had produced six healthy
lambs.
Dolly is to be stuffed and put on public display after a post
mortem examination. She will be put on display with another sheep
born at the institute, Morag, one of a set of twins, which was
donated after dying of a respiratory problem.
The museum already has a fleece from Dolly, and a spokesman said
it was right that a "Scottish sheep should reside in Scotland
for posterity".
Scandalous
Alan
Colman, a member of the team behind Dolly's birth, said: "It
highlights the foolishness of those who want to legalise reproductive
cloning. In the case of humans, it would be scandalous to go
ahead, given our knowledge about the long-term effects of cloning."
Expert on the ethics of human cloning, Dr Patrick Dixon, said:
"A key question is exactly what kind of progressive lung
disease she has had and whether that can be related in any way
to the cloning technology which produced her."
Professor Richard Gardner, chair of the Royal Society working
group on stem cell research and therapeutic cloning, said: "We
must await the results of the post-mortem on Dolly in order
to assess whether her relatively premature death was in any
way connected with the fact that she was a clone.
"If there is a link, it will provide further evidence of
the dangers inherent in reproductive cloning and the irresponsibility
of anybody who is trying to extend such work to humans."
Life, the national pro-life charity, said the death of Dolly
proved that cloning was unnecessary.
Trustee Nuala Scarisbrick said: "I would hope that this
wretched thing that has happened would convince the general
public that cloning is wrong and should be banned full stop."
The Religious Raelian sect’s associated ‘cloning company’
Clonaid claimed earlier this year to have cloned human babies
but, without any evidence, the scientific world remains unconvinced
.
l Last year, the long-cherished dream of cloning much-loved
family pets came a step closer when it was announced that American
scientists succeeded in cloning a domestic cat for the first
time. The cloned feline was introduced to the world last week.
The two-month-old tortoiseshell kitten, called Cc - short for
"carbon copy" - appears to be healthy.
Cats became the sixth mammal - after sheep, cows, mice, goats
and pigs - to be cloned with the nuclear transfer technique
used to produce Dolly.
But as with all the previously cloned species, the cloning success
rate is low. Cc was the only live birth out of 87 cloned embryos
implanted into surrogate mothers.
Although Cc, now just over a year old is a genetically identical
twin of the donor cat, it is far from a carbon copy. The pattern
on cats' coats is only partly determined by genes; it also depends
on the environment in the womb as the kitten embryo grows. Cc's
colouring is unique. The female kitten was created by Dr Mark
Westhusin and colleagues at Texas A&M University in College
Station, home of the much-vaunted ‘Missyplicity Project’
which has been trying, for the past six years, to create a cloned
dog but without any notable success.
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