US Study Finds All Cloned
Animals Abnormal

http://www.philly.com/mld/philly/news/breaking_news/4051490.htm

11 Sept 2002
U.S. Study Says All Clones Genetically Abnormal
BY MAGGIE FOX, HEALTH AND SCIENCE CORRESPONDENT
Reuters

WASHINGTON - Cloned mice have hundreds of abnormal genes, which
explains why so many cloned animals die at or before birth and proves it
would be irresponsible to clone a human being, scientists said.

The process of cloning introduces the genetic mutations, and there seems no
immediate way around the problem, Rudolf Jaenisch and colleagues at the
Massachusetts Institute of Technology reported.

"I think this confirms suspicions that I have always had and that many
others had that cloning is a very inefficient method at this point,"
Jaenisch said in a telephone interview.

"It is very irresponsible to think this method could be used for the
reproductive cloning of humans."

Even before Dolly the sheep became the first mammal to be cloned from an
adult cell, in 1997, researchers have known that cloning is difficult.

The most common cloning method is called nuclear transfer and involves
taking the nucleus out of an egg cell, replacing it with the nucleus from a
cell of the animal to be cloned, and then "reprogramming" the creation so
the egg begins dividing as if it had been fertilized by a sperm.

Only one of every several hundred eggs ever start dividing and of these,
only a small percentage result in pregnancies. Many of the animals that
survive to birth die soon after, or develop abnormalities of the lung, liver
and other organs.

Jaenisch and colleagues at MIT's Whitehead Institute, working with Ryuzo
Yanagimachi of the University of Hawaii, who was the first to clone mice,
made dozens of cloned mice and then looked at the activity of 10,000 genes
using a gene chip.

Writing in this week's issue of the Proceedings of the National Academy of
Sciences, they looked mostly at the placentas of the newborn mice, long
assumed to be the source of the problem, but also at the livers of some of
the clones.

GENE CHIP SHOWS ABNORMAL GENES

They found many abnormal genes. The pattern was so clear that they could
tell normal mice from cloned mice by looking at the results of the gene chip
study, they reported.

"There is no reason in the world to assume that any other mammal, including
humans, would be different from mice," Jaenisch said.

He said the finding should convince anyone who doubted the danger of trying
to clone a human, referring to last summer's debate between he and other
cloning experts, and three scientists who said they planned to try to clone
human babies to help infertile couples.

"It settles the old question ... about how normal can clones be," Jaenisch
said.

The three scientists have each said they are on the verge of creating a
cloned baby but none has produced evidence that convinces scientists such as
Jaenisch.

The issue has been debated in the U.S. Congress and competing bills would
outlaw attempts to clone a human being, and some would outlaw using cloning
technology in human beings at all.

Several cloning researchers have said their cloned livestock, such as
cattle, sheep and pigs, are normal and healthy if they get past birth.

Jaenisch believes genetic abnormalities will be found even in these
seemingly normal animals. Some of the abnormalities are simply not fatal, he
said.

Many of the problems the team found were in so-called imprinted genes,
involved in the development of the embryo. In the imprinting process only
the copies of a gene that a baby gets from its father are turned on.

"Almost 50 percent of those were incorrectly expressed," Jaenisch said.

That may mean that so-called therapeutic cloning, which uses cloning
technology to make human cells for use in medical treatments, would be safe,
he said.

"In therapeutic cloning you don't form an embryo," Jaenisch said, noting it
went to an early stage of development in which a ball of about 100 cells is
formed.

"In cloning most, if not all, problems arise during embryonic development,"
he added.