Curing diseases, saving rare species are clone prospects Scientists cite potential benefits, rather than abuses

February 25, 1997|By Jonathan Bor and Frank D. Roylance | Jonathan Bor and Frank D. Roylance,SUN STAFF

A British scientist's startling success in cloning a sheep has scientists talking eagerly about ways that animals might be replicated to conquer human disease or rescue species from the brink of extinction.

While scientists shared concerns about nightmarish abuses, most expressed doubts that people will rush to make copies of athletes, warriors -- or themselves.

One of the most exciting prospects, experts said, is the creation of barnyard animals that are living factories of pharmaceuticals.

There is also interest in producing exact copies of animals that carry genetic diseases. This would give scientists better models to watch the ways human diseases progress and to test `D therapies.

"I think it's very important to try to think about this very clearly and not to be overwhelmed by fear," said Ellen Moskowitz of the Hastings Center in Briarcliff Manor, N.Y., an institute for the study of medical ethics.

"This is just the kind of area where abuse is possible and overreaching is possible. But it sounds like there are potential benefits that could come out of this technology and I can't see any reason not to use it in those areas."

Cloning was one of the sensationalistic stories of the 1970s after the emergence of new techniques for genetic engineering. A science writer, David Rorvik, created a brief stir with a "nonfiction" book about a wealthy man who made a copy of himself.

It was a hoax.

Animal cloning seemed to drift into the realm of science fiction as the technology proved agonizingly difficult.

Meanwhile, ethicists and theologians turned their attention to more immediate issues, such as abortion and care of the dying.

Now, the birth of a lamb named Dolly -- the genetic copy of her mother -- is sure to be one of the scientific stories of the year, if not the decade. The lamb was created by a team led by Dr. Ian Wilmut, an embryologist at the Roslin Institute in Edinburgh, Scotland.

The breakthrough has numerous implications for the treatment of human disease, said Dr. John Eppig of the Jackson Laboratory in Bar Harbor, Maine.

Once scientists learn how to transfer the technology to other species -- say cows, pigs or rabbits -- they will want to copy animals that have inherited diseases that plague humans.

"If you had a porcine or a bovine model for cystic fibrosis and you were able to propagate large numbers of those animals, all of which would come down with that disease, you could study them prospectively and retrospectively," said Eppig, senior scientist with the laboratory.

For this purpose, scientists already make wide use of animals infused with human genes responsible for Lou Gehrig's disease and other illnesses. But Dr. Eppig said transgenic animals have limited value because genetic diseases are caused by many genes, not just isolated ones that have been identified as culprits.

Clones, in contrast, would carry the full complement of genes that trigger and modify illnesses.

Pharmaceutical factories

The British team is interested in clones as pharmaceutical factories.

Scientists, said Eppig, might do this by melding transgenic and cloning techniques. In theory, they could start out by inserting genes into a cow's mammary cells that produce helpful compounds that are not ordinarily found in milk. These could include cancer-fighting interferons or clotting factors that are needed by hemophiliacs.

Dr. John Strandberg, director of comparative medicine at the Johns Hopkins School of Medicine, said scientists would encounter new challenges when they tried to clone different species. "But the technical feasibility is probably there" to extend the method -- even to humans, he said.

Scientists noted that human cloning could be intended for good or evil: to make a new version of a dying child -- or the mirror image of an egotistical parent. Societal revulsion, they said, will probably curb the impulse to duplicate humans. And for now, there is a U.S. ban on the use of federal money to support human embryo research.

That doesn't mean that someone couldn't do it anyway.

"We already have good reason to be more closely regulating fertility practices that take place," said Moskowitz of the Hastings Center. "This is another reason we should redouble our efforts."

Dr. David Sussman, a geneticist with the University of Maryland at Baltimore, agreed: "I believe most people would find it unethical, and it's not clear how many individuals like themselves enough to want to raise copies of themselves."

Scientists were nonetheless intrigued by scientific questions posed by the prospect of human cloning.

Although he doesn't recommend that the technology be extended to humans, Dr. Marvin Reitz of the University of Maryland Biotechnology Institute speculated that a human clone might develop unique characteristics if it grows up in a different environment than the one that nurtured the original.

"I think the clone is going to be its own person, just as an identical twin is its own person," he said.

No super cattle

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