As the genetic carbon copy of another creature, Dolly the sheep the world's first cloned mammal doesn't really have parents in the normal sense. But Ian Wilmut, 57, the embryologist who led the experimental team that produced her in 1997, could be considered something of a father figure to the famous ewe. And since one ambition of Wilmut and his colleagues at the University of Edinburgh's Roslin Institute has been to strengthen the bond between humans and animals, his disclosure last week that Dolly is afflicted with premature arthritis was more than just the dry clinical announcement of a scientific development.
Despite his concern for his subjects' welfare, Wilmut's goal as a cloning pioneer is to genetically alter animals so they can eventually be used as a source for organ transplants and other potentially life-saving therapies for humans. "For exactly the kinds of things that have just been achieved with the pigs," he says, referring to two separate cloning experiments announced last week that produced pigs lacking a gene that prompts organ rejection in humans. PPL Therapeutics, a company affiliated with the Roslin Institute, delivered five such piglets on Dec. 25; the next day, rival Immerge BioTherapeutics said four similar miniature pigs had been born in September.
The early onset of arthritis in Dolly's knee and hip could have vast implications for cloning. "We'll never really be sure," says Wilmut. "But if the arthritis is due to cloning, it's one more piece of information about cloning's impact on animals. We already knew it's an inefficient process, with only a small proportion of the embryos becoming live offspring and some of those dying soon after birth. This may be another symptom."
Potentially lethal uncertainties like these have prompted some animal-rights activists to call for a halt to all cloning activity. Wilmut is undeterred. He says he is an agnostic, "though not hostile toward religion," and notes that his wife is a Church of Scotland elder. "We have laudable, reasonable objectives," he says. "But we do owe it to the animals to be particularly thoughtful about them and the way we use them."
Wilmut has enjoyed working with animals since his childhood in Yorkshire, where both his parents were schoolteachers. The sort of animal husbandry he now practices may not be what he had in mind when he set out to study agriculture at Nottingham University, but it's probably more lucrative. Despite last week's fall in the company's stock price in reaction to its competitors' pig cloning advances, Wilmut's 50,000 shares in Geron Corporation, a biopharmaceutical firm that is one of the Roslin Institute's partners, are still worth nearly half a million dollars.< A NAME="QA">
TIME: This news has prompted some animal welfare groups to call for a halt to cloning experimentation. Should we heed them?
WILMUT: No. We should do two things. There should be detailed monitoring of all the clones that we have, and then complete openness about what people are finding. We have suspicions that not everybody is being open.
TIME: Since your field is genetics, is there any special significance to the fact that one of your three children is adopted?
WILMUT: Before we were married we decided that we would probably choose to have only two children. Both were daughters and we liked the idea of having a son, so we adopted a boy. Once they get past infancy, there are a number of children who arenít adopted and are left in homes. We became attached to this lad who was three when we adopted him and is now 26.
TIME: Do you think youíll see animals used routinely as organ-transplant sources in your lifetime?
WILMUT: Yes. Give me 15 years, until Iím 72. During that period, I believe programs various labs have to genetically change pigs to make them suitable as organ donors will come through to clinical practice. I also believe the production of cells, from animals or from humans, for the treatment of degenerative diseases will come into routine practice. I also think that improvement to the technique will continue for much longer than 15 years.
TIME: If you needed a transplant and the technique were still experimental, would you use it?
WILMUT: That makes me sound like a hero. If your choice is you die or you take a chance by having an organ from an animal, I donít think thatís difficult. You take the organ and you are grateful.