Wilmut, Ian (1944-) is a British embryologist and genetic engineer who led the team that created a cloned sheep in 1996. Cloning is the process of using laboratory methods to create animals or groups of cells that have exactly the same inherited characteristics. The sheep, Dolly, was the first mammal cloned from an adult cell of another animal, and her birth became known throughout the world as a milestone in cloning.

Wilmut was born in Hampton Lucy, England, and raised in Coventry. He earned an undergraduate degree in agricultural science at the University of Nottingham. There he became interested in animal genetic engineering, a field involving techniques that alter the genes (hereditary material) or combination of genes in an organism. Genes are bodies in the cells of all living things that determine the organism's characteristics. By changing an organism's genes, scientists can give the organism and its descendants different traits.

In 1971, Wilmut received a doctoral degree from Darwin College, Cambridge University. Just after completing his doctorate, Wilmut produced Frosty, the first calf ever born from a frozen embryo.

Wilmut then joined the scientifically progressive staff of the Animal Breeding Research Station in Roslin, Scotland, a tiny village in farm country a few miles south of Edinburgh. In 1993, the Research Station became Roslin Institute, a nonprofit organization dedicated to understanding and improving the productivity, breeding, and welfare of farm animals.

Early successful cloning experiments had used cells from a very early stage of development. The Roslin Institute's first cloned sheep, Megan and Morag, were born in early 1996. They were produced from embryonic rather than adult cells, and their birth caused a great stir among scientists.

Most scientists did not believe that it was possible to manipulate adult animal tissue to produce a complete organism. As an animal develops before birth, cells begin to specialize as blood, bone, skin, and all other kinds of cells in the body. This specialization occurs because different genes become active or inactive. The scientists assumed that the inactive genes in adult, specialized cells could no longer direct the development of a complete animal.

Wilmut and his team of scientists reasoned that depriving an adult cell of food might force it into a kind of hibernation. They could then transfer its genes into another cell and stimulate that cell to begin dividing. They hoped that this stimulation would reactivate all the transferred genes, including those that had become inactive.

The team used this technique in creating Dolly. They removed the nucleus, which contains the genes, from a female sheep's egg cell. The scientists then replaced the nucleus with a “hibernating” nucleus from another adult female sheep. This transfer made the egg cell genetically identical to the adult sheep that contributed the replacement nucleus. After stimulating the egg with an electric charge, the scientists placed it in the womb of a third female sheep. The egg developed normally, and Dolly was born on July 5, 1996. Wilmut's team announced her birth early in 1997. It was the result of many attempts. Before producing Dolly, Wilmut's team had tried their technique about 275 times without success.

Dolly's birth created an international storm of controversy. Scientists, journalists, politicians, and others argued the ethics of cloning and the future possibilities created by cloning. The fear of human cloning created the strongest reaction. The British government announced in 1997 that it planned to withdraw its funding from the Roslin Institute's cloning study. Wilmut and his team received further support from an Edinburgh-based biotechnology company.

On July 25, 1997, the controversy erupted again when the team announced that they had produced a lamb with a human gene in every cell of its body. The lamb, Polly, was cloned from a fetal cell that contained a transplanted human gene.

Since the cloning of Dolly, scientists from Japan, the United States, and elsewhere have used a similar technique to produce clones of mice, cattle, and other mammals. Cloning may provide many benefits for human beings. For example, cloning could produce disease-resistant livestock, create new treatments for illnesses such as diabetes and Parkinson's disease, and even create animals that can manufacture donor organs for transplants to humans.

Cloning may present problems, however. Techniques have not been perfected, and scientists may find it difficult to produce consistently healthy clones. Moreover, many people regard the possibility of cloning human beings as unethical or against their religion's principles.

Wilmut continues his work at Roslin Institute. In March 2000, he was elected to the Royal Society of Edinburgh.