
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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