Why Clone? Part 2

by Food and Drug Administration (FDA)

(Page 3 of 3)

This analysis is not as easy as you might think, says Matheson. "We don't know what the composition of 'normal milk' is. It may all taste the same from the market, but it can vary a lot in each individual animal depending on its age, what it eats, and the time of lactation. Qualitatively, most of the same ingredients are always present, but quantitatively, their actual concentration varies from animal to animal." This may be true for meat as well since each animal is different just like each human is different. "Even though we think of a pork chop as a pork chop and a steak as a steak, they're each a little bit different from one another in chemical composition," adds Matheson.

The NAS report cited environmental concerns regarding genetically engineered fish and other animals that could escape into the environment, reproduce, or compete successfully for food and mates with wild animals. But this concern does not extend to cloned domesticated animals, since cattle and other livestock generally do not run wild and have no wild counterparts in the United States with which to interbreed.

Cloning may someday reduce the number of animals needed for food and fiber production, according to the report, but could also have adverse effects on animal welfare. Calves and lambs produced through cloning tend to have higher birth weights and longer gestation periods, which may lead to difficult births. Repeated exposure of individual animals to invasive procedures to harvest oocytes for SCNT is likely to cause pain and distress. In addition, the survival rate of cloned fetuses is low, and some survivors have health problems such as heart and lung disease.

Speculation surrounds the death of Dolly the sheep. Dolly had been diagnosed with arthritis in her hind limbs when she was about 4 years old. In February 2003, she was euthanized at the age of 8 because of a degenerative lung condition most probably caused by a virus. Critics blame cloning for Dolly's lung disease and her arthritis. But others attribute her health problems to being overweight and to becoming infected with a virus present in the barn in which she was kept.

Low rates of success are inherent in any new technology, says Page. "But the people doing this are becoming better technicians. We're making improvements in the way we handle cells and embryos. Efficiency rates continue to improve year after year, and more of the embryos are surviving to term and more of the calves are healthy."

The Humane Society of the United States (HSUS) has asked the FDA to ban sales of products from cloned farm animals and their offspring because of "serious concerns about the health and welfare of cloned animals."

"We condemn cloning as yet another move away from regarding animals as animals, and yet another development that will favor large corporations over small ones," says Michael Appleby, Ph.D., HSUS vice president for farm animals and sustainable agriculture. The HSUS commends the FDA for commissioning the NAS report and requesting that food from cloned animals not enter the marketplace. "These measures show an appropriate, precautionary approach," says Appleby, "and we trust the FDA will further this by putting more weight on the animal safety issues outlined in the report."

The NAS's job was to identify the potential risks of cloning; now the FDA is studying those risks to determine how to manage them. The FDA is developing two risk assessments: one describing the potential risks, if any, of consuming food products from animal clones and their offspring, and the other describing health risks to animal clones and their offspring. The FDA will use these assessments to develop an appropriate science-based regulatory approach, in the form of policy or guidance for industry, to manage any food and animal health risks. The public will have the opportunity to comment on this guidance, planned for release by the end of 2003.

In its commitment to a transparent process, CVM gathered together food producers and food consumers to share their perspectives on bioengineered and cloned animals at a three-day public workshop. Held in Dallas in September 2002, the workshop was co-sponsored by the Pew Initiative on Food and Biotechnology, an independent source of information on agricultural biotechnology.

CVM will continue to inform the public as it moves toward a decision on the type of regulatory structure that will be needed for cloned animals. "The public will be well informed and nothing is going to happen that they won't know about," says Sundlof.

Cloning versus Transgenics

Cloned animals and transgenic animals are sometimes mistaken to be the same, but they are different, says Larisa Rudenko, Ph.D., a molecular biologist in the Food and Drug Administration's Center for Veterinary Medicine (CVM).

Transgenic animals or plants are produced by adding or removing genes, or by altering the expression of their existing genes. This process can involve genetic information taken from different species or created in DNA synthesizing machines. When a gene for insulin, for example, is inserted into a goat, the animal could produce insulin in its milk, which would then be purified into an injectable form to treat human diabetes. And genes for growth hormone from one fish species transferred into the genome of salmon can cause them to grow rapidly.

Cloned animals are produced using bioengineering techniques but are intended to be biological copies of existing animals.

CVM is developing guidance for cloning food production animals. Future guidance for developing transgenic food animals will build on the cloning guidance and further study.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.