Sheep are a very ordinary sight in Scotland. Thousands of the gentle, woolly beasts graze on hillsides and roam country lanes. So why was the whole world buzzing last week over one quite plain-looking Scottish sheep named Dolly?
Scientists called the sweet creature "a mind blower," "an awesome work" and "science fiction come true." President Clinton said she represented "a remarkable scientific discovery." Dolly seemed to take her stardom in stride, nibbling straw and blinking softly. But news of her existence caused global excitement.
Dolly is a clone. From the length of her eyelashes to the swirling pattern of her wool, she's an exact copy of another sheep, an adult female, or ewe (pronounced yew).
Her life began in a laboratory. Scientists took one cell from a ewe and placed its nucleus, the command center containing the cell's genes, inside a sheep egg cell. The egg's own nucleus had been removed. After a zap of electricity, the cell began behaving like a newly fertilized sheep egg. It divided into more cells. The scientists placed the cluster of cells into the womb of another ewe, where it continued to develop into a lamb. The ewe gave birth to Dolly last July. Tests show that she's identical to the ewe whose single cell created her.
The astonishing difference between Dolly and other sheep is that all her cells carry only the ewe's genes. Genes are the instructions inside cells that determine what a living thing looks like and countless other traits. All naturally created mammals, including humans, have a combination of genes from both parents.
Now people are wondering if the world will soon see another incredible sight: a clone of a human being.
What Is Cloning Good For?
Dolly's cloners at the Roslin Institute, near Edinburgh, Scotland, say they weren't trying to invent a way to make human clones. The goal of their research is to help farmers.
If a sheep had wonderfully thick wool, a farmer could whip up an identical one, or several. A cow that produced a lot of milk? Same thing. Now farmers pair a male and female animal with such traits in hopes that their offspring will have the traits too. Cloning would be a faster, more direct way to get that result.
Some scientists say that messing with Mother Nature in this way is just too risky. One danger, admits Ian Wilmut, head researcher on the Dolly project, is that if an animal had a gene for something bad, such as a deadly disease, all its clones would carry the same defect. Farmers will have to be trusted to use the new technology responsibly, he said.
The Big One: Cloning Humans
Another ewe is one thing. But how about another you? Scientists say we are one step closer to cloning people.
But Ian Wilmut says his work with Dolly should never be tried on humans. In his country "it is illegal," he said. "We have briefed the authorities to make sure this technique is not misused."
The U.S. has no such laws, yet. "We don't have laws against cloning because nobody thought it could be done," says George Annas, a medicine and law expert at Boston University. But last week President Clinton asked a commission to study cloning for the next three months and recommend rules about it.
Human cloning might make it possible for childless couples to become parents (sort of). Sick people could use clones to "grow" replacement organs. Imagine a whole basketball team of Michael Jordan clones, or your own clone to do your homework. There's still a big problem: cloning a person may turn out to be impossible. Human biology is different from a sheep's. Researchers may find that we can never make a human clone.
Even the study of human cloning brings up tough questions. Real human cells would have to be used. If an experiment did not work out, researchers could end up with a defective copy of a human. After all, it took researchers 277 tries to produce Dolly. The other 276 eggs did not survive. Should people be used that way?
"Science is close to crossing horrendous boundaries," says Leon Kass, professor of social thought at the University of Chicago.
Many fear that even if cloning research is outlawed, very rich people will conduct secret cloning experiments. "I don't think we are going to be effective at all in stopping technological progress," says Harold Shapiro, head of the federal group studying cloning. "We've got some hard thinking ahead of us."
How Dolly Got Her Start