Published February 29, 2008
Imagine taking the most succulent, flavorful sirloin steak and copying it in every way to guarantee the same top-quality meat reaches your plate every time.
That meat lover's dream is about to become a reality.
It all began over a decade ago with Dolly the sheep, the first successfully cloned animal. Livestock cloning experts have been perfecting their science ever since.
Though Dolly's cloned relatives won't be making it to the American dinner plate just yet — very few other sheep have been cloned, resulting in insufficient data for food researchers — the Food and Drug Administration has given its stamp of approval to meat and milk from cloned cattle, pigs and goats as safe for human consumption.
"The food in every respect is indistinguishable from food from any other animal," FDA Food-Safety Chief Dr. Stephen Sundlof told reporters on Jan. 15. "It is beyond our imagination to even find a theory that would cause the food to be unsafe."
Animal Cloning 101
Livestock cloning requires two types of cell — one from the genetic donor and an egg from a healthy female of the same species.
The donor cell can be any cell that contains the full genetic blueprint, or genome, of the animal to be cloned, though skin cells are most commonly used. (Sperm and egg cells contain only half a genome and can't be used.)
The nucleus, the part that contains the genes, is removed from the egg cell and replaced with the nucleus of the donor cell. The two are fused using an electric current. The resultant egg is stimulated to promote cell division and placed in a culture for several days.
Once the early embryo is developed, the egg is implanted into a healthy surrogate mother of the same species until birth.
When the Clones Come Home
Experts are quick to point out the advantages of livestock cloning for producers.
If you have a prize bull, for example, that has sired offspring with top quality meat and milk, then you will want to clone him rather than breed him naturally, because there's no guarantee a naturally bred animal will consistently produce good meat — only 1 in 8,000 animals produce the best quality meat and the greatest yield.
"With cloning you get a genetically identical animal to the animal that you want to clone," says Leah Wilkinson, director of Austin, Texas-based livestock cloning leader ViaGen. "With normal breeding ... you have two parents — it's a sharing of genetic material, and you get whatever combination comes out."
Top-quality livestock also tend to be more food efficient, drink less water and produce less manure, which means they're less expensive to keep and have a milder environmental impact.
If the thought of eating cloned meat doesn't leave a lump in your throat, you may want to try it for health reasons.
"There is a [dairy] cow in New Zealand [that] has a higher level than normal of omega-3s in her milk, and her milk has less fat in it than a normal dairy cow," explains Wilkinson. "In her lifetime she may make 50 offspring. If you made a hundred clones of her, you then multiply her offspring to 5,000."
Still, America just may not be ready for cloned meat. Consumer polls show a definite wariness; in a 2006 survey conducted by the Pew Initiative on Food and Biotechnology, 64 percent of respondents said they'd prefer not to eat it.
The FDA got 30,000 comments from the public, most of them negative, before giving cloned food the green light.
Reports of organ abnormalities, early deaths of clones and higher-than-normal susceptibility to disease have caused concern among consumers and activist organizations that say there is insufficient scientific data to support the FDA's announcement.
Biochemist Mae-Wan Ho, founder of Britain's Institute of Science in Society and member of America's Union of Concerned Scientists, is a leading critic of livestock cloning.
"Nuclear-transplant cloning is very inefficient, highly damaging and lethal to both surrogate mothers and fetuses — therefore unacceptable on animal welfare grounds — and the resulting small percentage of even 'normal looking' offspring are abnormal in many genes," Ho says. "It is not clear they are safe to eat."
Cloning experts argue that the higher rate of abnormalities and earlier mortality of cloned livestock were initial setbacks largely due to poor quality testing, and now happen only in a minority of cases.
But how rigorous are safety regulations concerning cloned livestock, and will they ever be enough to convince reluctant consumers?
In the risk assessment, the FDA admits to some gaps in current biological knowledge, specifically regarding what causes epigenetic dysregulation — the cause of biological abnormalities in clones.
Though these may cause changes such as coat color, behavior differences and disruption of immune system and metabolism in the animals, these changes also occur in naturally bred animals, so checks are already in place.
But we won't be carving up the clones just yet. At a cost of $15,000 per cloned head of livestock, compared to $2,000 for a naturally bred cow, it is not yet cost-effective to slaughter the animals.
Cloned livestock, for the time being, will be grown for breeding, though their naturally bred offspring will eventually reach the table.
And despite the FDA's approval, another federal agency — the U.S. Department of Agriculture — has asked American livestock producers to indefinitely extend a voluntary ban, begun in 2001, on meat and milk from cloned animals and their offspring while the USDA initiates a transition period for consumers.
"What we've asked the companies to do is to continue the moratorium on cloned animals as people go through this period of acceptance and understanding, and looking at the issues that surround cloned meat and milk in the food market," said Bruce I. Knight, undersecretary for marketing and regulatory programs at the USDA.