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She may not have been exactly one of a kind but Dolly the sheep, the
first cloned adult mammal, was definitely unique.
Dolly, aged 6, was put to sleep by veterinarians on Friday after they
failed to cure her of a severe lung infection, her creators said.
Dolly's birth in July 1996 was kept secret for months while her creators
at the Roslin Institute and PPL Therapeutics Plc., a tiny biotech
company in Edinburgh, Scotland carefully checked her lineage. The
announcement of her birth, in February 1997, sent shockwaves around the
world.
Now cloning of farm animals has become almost routine and headlines were
made this week when the offspring of some cloned pigs made it to market.
Cloned animals are being bred to produce human proteins for medicine,
and for meat.
But no one would have dreamed of slaughtering Dolly, or any of her lambs.
Dolly was a breed called a Finn Dorset, with a white face and
cream-colored curly wool. Hand-fed from birth, she was friendly even
after she outgrew the curious lamb stage.
In contrast to her hardy cousins, put out to graze on steep hillsides in
Scotland, Dolly lived indoors. She reared up on her hind legs to nuzzle
visitors, looking for handouts.
DEATH TO BE AUTOPSIED
Some scientists believe this behavior, and not her lab-dish origins, led
to Dolly's well-documented arthritis. "There is a very real chance
Dolly's illness had nothing to do with cloning," said Dr. Robert Lanza
of Advanced Cell Technology in Massachusetts, a private firm doing
cloning research.
"There is a virus ... that sheep get at almost precisely Dolly's age.
This virus can cause arthritis and respiratory infections, particularly
in animals raised indoors," he said in a telephone interview.
Dolly's creator, Ian Wilmut, said her body would be carefully autopsied
to determine the cause of death.
"Obviously it is very sad news. We were all hoping Dolly would live to a
ripe old age," said Lanza. "She's a symbol of all the research that we
are doing."
For Lanza her death illustrated why most scientists oppose cloning a
human baby. "Dolly's death confirms what we all know -- which is that
there are problems with cloning," he said. "Cloning is still just as
much an art as a science."
Shares in California-based Geron (NasdaqNM:GERN - News), which bought
the rights to the technology that created Dolly, fell 16 percent on the
news but later rebounded.
Dolly's mother/twin died years before Dolly was born. She was made from
a frozen cell taken from the mammary gland of the anonymous ewe and
Wilmut said he named her after Dolly Parton, the American singer famous
for her own mammaries.
While Dolly is best known for being an almost precise copy, she was
unique in her birth. Wilmut's team tried to clone 276 sheep embryos in
an experiment that resulted in just one lamb -- Dolly.
Mike Bishop, former president of the privately owned firm Infigen Inc.,
which also clones farm animals, said Dolly's death was clearly premature.
"We've got ewes here that are eight, nine years old," Bishop said from a
farm in Wisconsin. "We are in the middle of lambing now in the frigid
Midwest and we have ewes that are eight, nine years old that are lambing."
Most sheep never make it to old age and are culled as soon as they
become unproductive, he noted.
"Sometimes if you have got that special ewe that deserves the right to
live out her normal life ... like she has been a real trooper,
delivering twins every year ... they'd like to see them live out their
lives to the end," he said.
Dolly, all would agree, was a trooper.
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