They cloned old Bessie

Steven Novella wants you to understand cloned beef. Get informed, and get passed rhetoric and uninformed fear.

The FDA has declared that cloned beef and milk are probably safe. This announcement was based upon a review conducted by the National Research Council at the request of the FDA. For the last several years the meat industry has upheld a voluntary moratorium on the sale of products from cloned animals. Some fear that this new announcement by the FDA is premature and will lead to the lifting of the moratorium. Others hail the announcement as a sign of welcome progress. Meanwhile, the majority of Americans are weary about cloned product amid widespread misunderstanding. So what’s the deal with cloned beef?

The basics of cloning is this - the process begins with a newly fertilized embryo, which has the potential to develop into a mature animal. The nuclear DNA, the instructions for making the entire organism (almost), is then removed from the embryo. It is then replaced with the DNA from the cell of an existing mature animal. The result is an almost exact duplicate of the mature animal from whom the donor DNA was taken.

I qualified the above with a couple of “almost’s” because nuclear DNA is not the complete list of instructions for making a grown animal - a small amount of DNA is mitochondrial, found in the small organelles inside cells that are responsible for energy production. Also, clones differ from their “parent’ in that they did not develop in the same womb, and the environment of the womb has an effect on development. In fact, identical twins are more similar to each other than clones.


Contrary to the common portrayal in science fiction, clones are not produced as mature creatures nor do they have the memories of their donor. They grow from an embryo just like any animal. If the process works then the result should be a perfectly normal and healthy animal. There is a high number of birth defects in cloned animals, but that is a technological problem, resulting, likely, from damage during the cloning process or some stress that the process places on the embryo. But there is no theoretical reason why clones should not be normal organisms - they are not monsters.

Also, cloning needs to be distinguished from genetic engineering, where the DNA is altered in order to change an organism. Clones are not necessarily genetically engineered.

If the process is so difficult and the result is a normal animal, why is the farming industry even interested in cloning? Well, for maximum efficiency - highest yield of the highest quality product - farmers prefer to use the best plants and animals. This is usually accomplished through selective breeding, a process that has served humanity very well and has, in fact, created most of the plants and animals we eat. Almost nothing we eat exists as it evolved in nature prior to human tinkering. But this is a slow and unpredictable process. What if a farmer comes into possession of an exceptional cow, a perfect pig, an enviable fowl? Traditionally they would use that animal to breed more like it, but often the offspring are not as optimal as the parent. If they could clone the animal, however, they would have an endless supply of perfection - they could lock into place whatever gains they made by prior breeding.

What are the objections to cloning? From a scientific point of view there are no theoretical concerns about cloned plants and animals for human consumption. The only real concern is that of uncertainty - that the cloning process may have resulted in an unforseen effect. This latest study essentially looked into that question - do the cows seem normal. The answer is that they could not detect any problems, but answers in the negative - claims for the absence of something, in this case the absence of any anomalies, are only as good as the thoroughness and sensitivity of the search. So while I think that the cloned animals probably are fine, and the research that has been done so far is very reassuring, we can’t rule out an undetected anomaly.

Another concern, not related to the safety of clones, is that of genetic diversity. The farming industry has increasing relied upon fewer and fewer varieties of plants and animals. This means that genetic diversity has been dramatically reduced in the last century, as the multitudes of local varieties have been replaced by a sea of monotonous optimization. Concern is not just nostalgia for lost varities. Genetic variation takes a long time to emerge, and it is a hedge against blight and extinction. We should be cautious before we put all of our genetic eggs in one basket. Cloning has the potential of exacerbating this problem significantly - as single varieties may be replaced by single genetic individuals.

Among the public, however, it seems that the biggest resistance to cloned products is simple disgust. Disgust is a specific emotion that evolved to protect individuals from tainted or bad food. We don’t have to do a chemical analysis of food prior to eating it, or way the risks vs benefits of possibly spoiled nutrition. Rather, our emotions of hunger and disgust battle it out, and one wins. Disgust (and the enjoyment of food on the positive side) makes the decision for us. But emotion decisions, while efficient, are not always rational or optimal. There are things that may trigger our disgust emotion even when there is no health risk - and I think that cloned food products fit into this category.

Clones are weird, unknown, and therefore frightening, so they trigger our disgust emotion. But this also means that over time, familiarity will lessen that reaction, and eventually eating cloned food will be ordinary and accepted. Don’t expect cloned beef on the shelves anytime soon. For now it seems that the industry is still testing the waters. But I do predict that cloned beef is in our future.