Milestones in Cloning (Cont.)
l1984- Steen Willadsen produces a live lamb from early sheep embryo cells in a process known as twinning. It is later used on other animals.
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l1995- Ian Wilmut and Keith Campbell create the world’s first cloned sheep, Megan and Moran, from embryo cells.
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l1996- Ian Wilmut and Keith Campbell clone the first sheep from adult cells, named dolly. At the age of 6, dolly is euthanized when veterinarians discover she has progressive lung disease. Research suggests that she may have been susceptible to premature aging.
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l1998- James Thomson and John Gearhart announce that they have established the first cultures of human embryonic stem cells, derived from fertilized human eggs before they could grow into specialized cells.
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