Word: wilmut
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...Before Dolly, no one thought it was possible to turn back time, especially where biology was concerned. Once a cell started on its march of development, nothing, absolutely nothing, scientists thought, could turn it around again. Dolly, the cloned sheep, proved this biological maxim wrong in 1996, when Ian Wilmut was able to coax an aging mammary cell to become an entirely new sheep by giving it a home in a hollowed-out egg. And since every scientific experiment just begets more experiments, Dolly's birth got researchers to wondering: If the egg can reprogram a cell, is it possible...
...adult cell (in Dolly's case, a cell from a ewe's udder). The two components are electrically fused and chemically activated to trick the hybrid cell into dividing like an embryo. Not surprisingly, the process doesn't always go right. "I call it a lottery," says Wilmut. "Even if you use the same method as consistently as you can, you may get some clones with severe abnormalities and some that have only minor ones...
...large-offspring syndrome. Those clones are born larger than normal and have trouble breathing in their first few weeks. Most of the surrogates that gave birth to them experience prolonged pregnancies and sluggish, difficult labors, which may have something to do with their distended and enlarged placentas. Some of Wilmut's cloned sheep were born with incomplete body walls, with muscles and skin around their abdomen that failed to properly join. Other scientists have reported abnormalities in kidney and brain function. In still other clones, the heart does not develop normally, and the walls that are supposed to separate fresh...
...older the cell. Dolly, a clone of a 6-year-old ewe, had cells whose telomeres were closer in length to those of her biological mother than to those of a baby lamb. We will never know, though, whether her shortened telomeres would have shortened her life. In 2003 Wilmut and his team decided to put Dolly to sleep after she developed lung cancer caused by a viral infection common among sheep. An autopsy revealed that she was otherwise normal...
...Jaenisch and Wilmut both see a role for cloning in treating human diseases--and perhaps someday conquering some of man's most intractable conditions. Wilmut and others have already created cow, sheep and pig cells genetically engineered to produce a particularly beneficial human protein, then cloned those cells to generate live animals able to make copious amounts of the target protein in their milk. It may be another 10 years or more before that approach yields anything safe and reliable enough to be used in real patients, and there is no guarantee that it will ever be successful...