This week (Feb. 14) in 2003 the world, or at least the scientific world, mourned the death of a cloned sheep named Dolly, who was not the first animal to be cloned, but the first to be cloned from the cell of another animal. Her cloners were doctors Ian Wilmut and Keith Campbell of the Roslin Institute at the University of Edinburgh in Scotland.
Doctors Wilmut and Campbell used a somatic cell from another sheep’s mammary gland to clone Dolly, thereby proving that a healthy clone could be produced from just a specific part of another body — in this case an adult cell. She was named Dolly because, Dr. Wilmut stated, “Dolly was derived from a mammary gland cell and we couldn’t think of a more impressive pair of [mammary] glands than Dolly Parton’s.”
Unsurprisingly, Dolly’s creation generated lots of media coverage, not all of it positive because the cloning of life was, and remains, controversial, especially in the religious world, where it is seen as an attempt by scientists to “play God.”
Nevertheless, Dolly became a celebrity — Time magazine devoted a special issue to her, dubbing her “The World’s Most Famous Sheep.” She lived her entire life at the Roslin Institute, where she was successfully mated with a Welsh mountain ram, producing six lambs, Bonnie, Sally, Rosie, Cotton, Darcy and Lucy.
Dolly’s death was also somewhat controversial. She was euthanized after developing a progressive lung disease, and there was speculation that Dolly had died prematurely because, genetically, she was actually six years old when she was born, that being the age of the sheep she was cloned from. This theory fit with the fact that Dolly’s breed of sheep usually lived to be 11 or 12, and Dolly died at age six.
Roslin’s scientists countered that lung disease was not unusual in sheep, and sheep kept indoors were particularly susceptible to the disease. For security reasons, given her celebrity, Dolly spent lots of time indoors.
In any event, Dolly’s successful cloning led to other cloned animals, including horses, bulls, deer and pigs, and one beneficiary of cloning has been endangered species. In 2009, a Pyrenean ibex, a mountain goat that was thought to be extinct, was cloned, and while it died shortly after birth, it was a significant first step in saving endangered and nearly extinct species.
Speaking of endangered species, or — if you are a believer in climate-change — nearly extinct ones, in 2007 Dr. Wilmut stated that the technique used to clone Dolly and other animals will probably never be successful with respect to cloning humans, which, unsurprisingly, has done nothing to dampen speculation in the scientific world that this will one day be possible.
