Cloned cells -- Frankenstein or savior of humanity?
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By Maggie Fox, Health and Science Correspondent
WASHINGTON, Nov 12 (Reuters) - They said it was coming and now it
has happened -- the technology that started with cloning Dolly
the sheep has led to the cloning of an adult human cell.
"They should never, ever have done this," said Jeremy
Rifkin, a writer and activist on biotechnology issues. "We
don't know what kind of creature could develop from that."
"It's part of a larger biotechnology question that we are
going to have to address about what proportion of genetic
material makes something one species and not another," said
Lori Andrews, a professor at Chicago-Kent College of Law and an
expert on the issue of the ethics of cloning.
Scientists at the Massachusetts-based biotech company Advanced
Cell Technology Thursday said they had fused human cells into cow
eggs to grow stem cells for tissue transplants, not to grow an
embryo that would essentially be a human clone.
Stem cells are capable of growing into any kind of cell in the
body. Scientists want to harvest them as tissue transplants to
treat ailments ranging from Parkinson's disease, caused when
certain brain cells die, to the type of diabetes caused when the
immune system destroys pancreatic cells.
James Robl, Jose Cibelli and colleagues took some of Cibelli's
cells, either from inside his cheek or from his leg, hollowed-out
cow eggs and used a pulse of electricity to get the nuclei of the
human cells to fuse into the cow eggs.
The cells started developing just as if they had been fertilised.
"We grew them up as an embryo for about a week, about eight
or 10 days, and then grew them as an embryonic stem cell cluster
for about two weeks," Robl said.
Other scientists at the University of Wisconsin beat them to the
punch last week, by growing such stem cells from embryos donated
at fertility clinics. They, too, hope to grow tissues for
transplantation.
Critics say both groups have already gone too far.
"I think there should be an immediate ban, that Congress
should immediately move on this company," Rifkin said.
In April Rifkin and cellular biologist Stuart Newman of New York
Medical College applied for a patent to cover human-animal
chimera technology in the hope of preventing just such
experiments.
"The developing embryo is a human embryo inside a cow egg.
That means it is going to share with the cow cytoplasm as it
develops," Rifkin said.
"We don't know what kind of creature could develop from
that.
There is no precedent in history. It will be mostly human as it
develops but it will share information and biological matter from
the cow egg," he added.
Robl says the human genes would take over and only a little bit
of mitochondrial DNA from the cow would remain. Dolly the sheep,
cloned in Scotland in 1996, is similarly not 100 percent a clone
-- she carries a little bit of such mitochondrial DNA from the
donor sheep egg used to make her.
Last January, Neal First and colleagues at the University of
Wisconsin said he had cloned animals of several species using
hollowed-out cow eggs, although none were successfully implanted
into an animal and grown.
Many animals already exist that carry human genes. Cows have been
made that produce human proteins in their milk, as have sheep,
pigs, rabbits and mice. All sorts of mice used in research carry
human genes.
But Andrews says Advanced Cell's creation is different.
"When you insert a human insulin gene or make an oncomouse,
you have created an entity that doesn't have the potential,
doesn't have the genetic information to make a whole human
being," she said in a telephone interview.
"But by using the entire genetic makeup for a human being,
what you have done is to create a potential human embryo."
In many states this is already against the law.
Dolly was cloned by a Scottish company in July 1996. Cloners at
the Roslin Institute in Edinburgh used electricity to fuse the
nucleus from one sheep's cell to another sheep's egg, and then to
reprogram that new egg so it started growing into a lamb embryo.
Last April Dolly gave birth to her first lamb after being
naturally mated with a ram.