Don't expect to be eating cloneburgers anytime soon. At $13,500 per head, cloned cattle are just too expensive for the dinner table. But the great-grandchildren of clones? Those may well be on their way to the menu, and we might not even know it.
The intricacies of clone-tracking served as the first course on the menu of news conferences at the American Association for the Advancement of Science's annual meeting - a scientific feast that began today in Boston and continues through the President's Day weekend.
Clones can and should be tracked as they make their way through feedlots and food processing systems, said Patrick Cunningham, a geneticist who wears three hats. He's a researcher at Trinity College in Dublin; chief scientific adviser to the Irish government; and the co-founder and chairman of IdentiGen, a company that has developed DNA tracking methods.
IdentiGen's technology already is being used to trace meat back to its source based on DNA sampling - for example, to find out where an E. coli outbreak came from or to assure consumers that their hamburger didn't come from a genetically modified cow. Cunningham said somewhere around 70 to 75 percent of all beef in Europe was being tracked, with a "DNA eye in the sky supervising the whole thing."
The barcode for beef takes the form of 30 to 40 biomarkers, or SNPs (single nucleotide polymorphisms). All those barcodes are retained in a database that can be matched up with animal products, "right down to the hamburger," Cunningham said.
The same approach could be used to identify products from cloned cattle. "You track a clone the same way you track an individual in any population," Cunningham said.
The companies that sell cloned cattle are already working on a somewhat lower-tech registry for keeping track of their animals as they move through the supply chain, said the president of one of those companies, ViaGen's Mark Walton.
Last month, the Food and Drug Administration determined that food products from cloned cattle, pigs and goats were "as safe as food we eat every day." However, companies are still holding off from selling food from clones, primarily for marketing reasons. And Walton doubts that the clones themselves will be gobbled up for mass consumption anytime soon -basically because it costs almost 10 times as much to create a clone as it does to make a calf the old-fashioned way.
"If you think steak is expensive today, think about having a feedlot full of $13,500 animals," Walton joked.
Cunningham agreed. "I don't believe cloned food is realistic here in America or in Europe in our lifetime," he said.
Today, cloned animals are valued primarily as sires. Theoretically, a prize bull could be copied, so that a bevy of bulls could pass along the genetic advantages through more traditional breeding techniques. Walton said that's already happening. "I'm aware of one bull [from which] over 60,000 straws of semen have already been sold," he told me.
If people wanted to avoid consuming milk or meat from a cloned bull's offspring, could they do it? How far down the breeding line could a "no-clone zone" extend? Could IdentiGen's system detect a clone's progeny?
"Offspring of clones - yes, we can do," Cunningham told me. "It's a bit more challenging, because you only have half of the clone's genotype in the offspring, and it's mixed up with, usually, the maternal contribution. But that's feasible. I think once you move to the grandchildren and the great-grandchildren - first of all, I don't see where it would be justified, but I don't think it's feasible, either."
Doug Gurian-Sherman begs to differ. He's a senior scientist at the Union of Concerned Scientists, which is opposed to cloned food.
"It certainly can be done, with ear tags that have barcodes," he told me by telephone after today's news conference. "It's feasible to do, though it could be technically challenging."
His chief concern isn't so much the possibility that there's some nasty twist of DNA in a cloneburger - or hamburger made from the great-grandchild of a clone. Rather, he's worried that over time, the rise of the clones will reduce genetic diversity and gradually make the entire species more vulnerable to the sorts of problems that come with agricultural monocultures.
Even efforts to create disease-resistant cattle through cloning could backfire, Gurian-Sherman argued. "The more genetic uniformity you have, [the more] you're going to leave yourself open to dozens of other diseases," he said.
"The bottom line is that the most important public health issue is going to be that uniformity issue," Gurian-Sherman said.
How far do you think a no-clone zone should extend? Do you think a "clone-free" label should apply not only to the cow in question, but to the cow's family tree as well? Is that necessary, or even realistic? Check out the case for clones at CloneSafety.org, the case against clones at the Center for Food Safety - and then weigh in with your own opinion below.