Dolly (sheep)
The ewe named Dolly (July 5,1996-February 14, 2003) is the first mammal to be successfully cloned from an adult cell. She was created at the Roslin Institute in Scotland and still lived there until her death seven years later. The name "Dolly" came from a suggestion by the stockmen who helped in the process, in honor of Dolly Parton, because the cloned cell was a mammary cell [1]. The particular technique that was made famous by her birth, is somatic cell nuclear transfer, in which the nucleus from one of the donor's non-reproductive cells, is placed into a de-nucleated embryonic cell (which is then coaxed into developing into a fetus). When Dolly was cloned in 1996 from a cell taken from a 6 year old ewe, she became the center of a controversy that still rages on today.
The Controversy
In 2002, Dolly's creators have disclosed that she is beginning to show advanced signs of senescence at an unusually young age.
Of particular concern is the early onset of a potentiallly debilitating form of arthritis. With these new findings, some have speculated that since Dolly was cloned from a 6 year old ewe, and now she herself is 5, then she is genetically 11 years old. This has further fueled worry among some that this form of cloning may not be appropriate for mammals, and there is a consensus both within and outside the scientific community that the unforseen effects of cloning on the clone suggest that human experiments in reproductive cloning would at this point be highly unethical.
Supporters of this method of cloning counter that the technique used to clone Dolly simply needs to be refined. Others contend, however, that with our very limited understanding of the nascent field of applied genetics, we cannot, and should not, attempt to control the action of so many genes at once. Yet many outside of the scientific community have stated that this is vindication for their initial assertions that any form of cloning is ethically wrong and should be banned.
Her End
Dolly was put down on February 14, 2003 due to complications from an apparently-congenital lung disease.