By CRG Staff
How is livestock cloned?

Livestock cloning has been accomplished through embryo splitting - in which a multicellular embryo is split into "twins" - and through somatic cell nuclear transfer (SCNT), in which the nucleus of an adult cell is inserted into an egg which has had its own nucleus removed. A team of scientists led by Ian Wilmut used the latter method to clone Dolly, but Wilmut and others have since shifted their favor toward a newer approach which skirts concerns about obtaining eggs and destroying embryos. This method, pioneered by Kyoto University's Shinya Yamanaka, reprograms adult cells to an embryonic- like state - known as induced pluripotent stem cells - creating a blank slate from which the cells can emerge as any kind of cell in the body. This approach is less difficult and expensive to carry out than SCNT, but remains inefficient and not fully understood.

Is livestock cloning legal?

Some form of animal cloning is legal all over the world; the issue arises with the prospect of cloned animal product in the food supply. Surveys in Europe and the U.S. have shown a general public distaste for the idea of eating clones; however, in the U.S., the Food and Drug Administration has concluded that the meat of clones shows no significant nutritional difference from the meat of non-clones, and products derived from clones and the progeny of clones can be legally sold in the U.S.

Furthermore, FDA Center for Veterinary Medicine director Stephen Sundlof asserts that FDA does not have the authority to require labeling of food from cloned livestock if that food is not determined to be substantially different from the product of non-clones. He suggests, however, that FDA might police "clone-free" labels if they imply that food from clones or their progeny is less safe. This recalls the disputes over bovine growth hormone (rBGH) labeling in milk: despite legal actions by Monsanto, which produces rBGH, states have generally allowed milk to carry "rBGH-free" labels so long as they include a disclaimer that milk from cows treated with bovine growth hormone is not significantly different.

Does this mean cloned meat is already at the grocery store? Right now that's unlikely for two reasons. Firstly, cloned livestock is still in its early stages: a 2006 industry estimate put the numbers at only 600 cloned cows and 200 cloned pigs in the U.S. Secondly, because of the expense of successfully cloning an animal, clones would be for 'breeding, not eating.' That is, farmers would have the animals with the best genetics cloned for use as breeding stock, in order to preserve those genetics and sell them to other producers. Selling a cloned animal for meat would be quite a waste of money. It could well be, however, that the products from the progeny of clones will soon appear unannounced on grocery store shelves.

Besides the 'yuck' factor, what's wrong with cloning livestock?

Despite the FDA's confidence, there are some potentially serious food safety concerns. According to Wilmut himself, along with MIT's Rudolph Jaenisch, the technology used to locate early abnormalities in clones does not reveal epigenetic reprogramming, which can lead to undetected abnormalities which do not appear until later, could cause food safety problems - and are passed on to future generations.1 The National Academy of Sciences has echoed these concerns.2 Jaenisch points out that in a cow, some abnormalities may not become visible until as many as 15 years of age. To put that into perspective: Dolly was cloned only 12 years ago. Some of the abnormalities associated with cloning raise animal welfare concerns, as they can be fatal to the clone or the host 'mother.'

While some farmers might find use for livestock cloning, the companies carrying out the cloning - such as Viagen and Cyagra - stand to benefit most. Efficient cloning technologies could usher in the ability for laboratories to create and sell genetically modified livestock. In other words, livestock cloning could be just the tip of the iceberg.  


1. Jaenisch, Rudolf and Ian Wilmut. "Don't Clone Humans!" Science 291. March 30, 2001.
2. "Cloned Food: Coming to a Supermarket Near You?" The Center for Food Safety, January 2007.
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