Dolly (sheep)
Dolly was cloned by Keith Campbell, Ian Wilmut and colleagues at the Roslin Institute, part of the University of Edinburgh, Scotland, and the biotechnology company PPL Therapeutics, based near Edinburgh. The funding for Dolly's cloning was provided by PPL Therapeutics and the Ministry of Agriculture. She was born on 5 July 1996 and died from a progressive lung disease five months before her seventh birthday (the disease was not considered related to her being a clone). She has been called "the world's most famous sheep" by sources including BBC News and "Scientific American".
Hwang Woo-suk
In the late 1990s, the method that scientists used in cloning was somatic cell nuclear transfer, which is the same procedure that was used to create Dolly the sheep. This laboratory technique begins when an egg is taken from a donor and the nucleus is removed from the egg, creating an enucleated egg. A cell, which contains DNA, is then taken from the animal being cloned. The enucleated egg is then fused together with the nucleus of the cloning subject's cell using electricity. This creates an embryo, which is implanted into a surrogate mother through in vitro fertilization. If the procedure is successful, then the surrogate mother will give birth to a baby that is a clone of the cloning subject at the end of a normal gestation period. In 2014 researchers were reporting cloning success rates of seven to eight out of ten but in 1996 it took 277 attempts to create Dolly.