While much of the press coverage focused on the potential of cloning humans using this approach, the immediate scientific impact is in genetic engineering, where this success removes a key barrier to feasibly manipulating the genes of farm animals. For example, transgenic sheep have recently been genetically engineered to secrete into their milk a protein called alpha-1 antitrypsin, which attacks the enzyme elastase and so may be helpful in relieving the symptoms of cystic fibrosis. Similarly, special transgenic goats have been engineered to produce human antithrombin III, a protein that controls blood clotting, and transgenic cows add nutritious human lactalbumin in their milk. The difficulty in using transgenic animals to improve agriculture and medicine is getting enough animals.
Breeding produces offspring only slowly.
Now the holy grail of agricultural genetic engineers seems within easy reach. It was 14 years before technology advanced far enough for anyone to take up Spemann's challenge. The experiment did not work when done this way, but partial success was achieved 18 years later by the British developmental biologist John Gurdon. In 1970 he repeated the experiment, but inserted nuclei from advanced toad embryos rather than from adult tissue. For 24 years nuclear transplant experiments were attempted without success.