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Is It a GMO or Not?

A new generation of genetically modified organisms will be genetically indistinguishable from non-GMOs.

By Michael White


A horned dairy cow. (Photo: iamsch/Flickr)

What is a genetically modified organism (GMO)?

This is not a question we usually ask when we talk about GMOs, because the answer seems obvious: GMOs are organisms created by genetically engineering a gene from one species into the DNA of another. This definition of GMOs has been correct for the two decades that they have been sold commercially in the United States. The most widely produced GMOs are herbicide- and pest-resistant corn, soybeans, and cotton, whose special traits are due to genes taken from bacteria.

But what if a GMO did not carry foreign genes? What if a GMO could not, by any possible genetic test, be distinguished from something produced by conventional agricultural breeding? Would we still consider it a GMO?

This is the question raised by a new generation of genetic engineering technologies, technologies that make it possible to engineer subtle genetic changes that don’t involve the transfer of genes between different species.

Although the scientific consensus is that commercially sold GMOs are no less safe than conventional foods, current GMOs do contain material that is not present in their conventional counterparts. It’s this unnatural presence of the foreign genes in GMOs that make people uneasy about eating “Frankenfoods.” And most of us, understandably, want to know what’s in the food we’re eating — hence the wide support for laws that require GMO foods to be labeled as such.

Scientists at the company created hornless dairy cows by using genetic engineering to put a naturally occurring bovine mutation into a normally horned cattle breed.

There are many potentially useful genetic modifications that scientists can now make to crops and livestock that don’t involve adding foreign genes, however. An example of this kind of next-generation genetic engineering was recently published by the small, Minnesota-based biotechnology company Recombinetics. Scientists at the company created hornless dairy cows by using genetic engineering to put a naturally occurring bovine mutation into a normally horned cattle breed.

Why do this — why would you want hornless cattle, and why use genetic engineering to make them? The answer to the first question is that horns are dangerous, to both farmers and other cows. And so, for safety, millions of calves are de-horned each year, using a painful procedure that is criticized as inhumane by animal welfare groups. Because of concerns about de-horning methods, several major corporations from Starbucks to Walmart have pushed their meat and dairy suppliers to find ways to avoid painful de-horning procedures.

For the beef industry, this isn’t a big problem because popular breeds of beef cattle are, for the most part, already hornless or “polled.” This is because these breeds carry a naturally occurring mutation that causes hornlessness. But popular dairy breeds, like Holstein, generally don’t carry the polled mutation, and so dairy farms rely heavily on physically de-horning their cows.

The most obvious way to avoid de-horning is to try to breed the polled mutation into Holstein herds. But this isn’t so easy for two reasons: First, breeding programs will take decades to create a high fraction of hornless Holsteins. And second, polled bulls currently available for dairy breeding don’t have high-quality dairy traits, making it challenging to breed more polled Holsteins without sacrificing what breeders call the “genetic merit” of the existing herds.

To get around these challenges, scientists at Recombinetics turned to genetic engineering. Supported by a grant from the Department of Agriculture, they used a DNA editing technology to deliberately make Holstein embryos with a polled mutation that naturally occurs in other breeds. They then implanted those embryos into a cow, who, a few months later, gave birth to hornless calves. By examining the DNA of those calves, the scientists could identify the polled mutation, but, otherwise, the DNA editing technology left no trace. Genetically, you wouldn’t be able to tell that these animals are GMOs.

This story raises several important issues that will become unavoidable parts of the debate over GMOs. The first is, how should we define what counts as a GMO — do we care about the process used to create them, or simply the end result? Second, GMOs clearly can be used to address important ethical and environmental problems in agriculture that are difficult to tackle by other means. As the technology gets better and less expensive, more companies will design GMOs to solve these problems, especially small companies that aspire to achieve some social good. That means choosing whether or not to eat a GMO won’t be as simple as deciding whether to avoid food with foreign genes produced by Big Agriculture. Sometimes, GMOs might be an ethical choice.