posted on 2009-12-08 by JPerez
By  J. Madeleine Nash/Chicago   Monday, Nov. 08, 1993

///...Want to peek into a crystal ball and glimpse at the future of cloning? One way might be to look at the livestock industry, the proving ground for reproductive technology. More than a decade has passed since the first calves, lambs and piglets were cloned, and yet there are no dairy herds composed of carbon-copy cows, no pigpens filled with identical sows. While copying particular strains of valuable plants such as corn and canola has become an indispensable tool of modern agriculture, cloning farm animals, feasible as it may be, has never become widespread. Even simple embryo splitting, the technique used by the George Washington University researchers on human cells, is too expensive and complicated to take off commercially. "Cloning," says George Seidel, an animal physiologist at Colorado State University, "remains very much a niche technology."

But people have certainly tried to turn livestock cloning into a booming branch of agribusiness, and they're still trying. Wisconsin-based American Breeders Service, a subsidiary of W.R. Grace & Co., now owns the rights to cattle-cloning technology developed by Granada Biosciences, a once high-flying biotech firm that went out of business in 1992. The process calls for single cells to be separated from a growing calf embryo. Each cell is then injected into an unfertilized egg and implanted in the womb of a surrogate cow. Because the nucleus of the unfertilized egg is removed beforehand, it contains no genetic material that might interfere with the development of the embryo. In theory, then, it ought to be possible to extract a 32-cell embryo from a prize dairy cow and use it to produce 32 identical calves, each brought to term by a less valuable member of the herd. In practice, however, only 20% of the cloned embryos survive, meaning that instead of 32 calves, researchers generally end up with only five or six.

Read more: http://www.time.com/time/magazine/article/0,9171,979547,00.html#ixzz0Z9OA0LOb