GMOs 101: Getting down to basics

MSU researchers offer a primer on the basics of GMO foods, breaking down an often difficult and controversial subject.

An online search for “GMO” returns more than 88 million results – a tangled mess of frightening images, dense data, skepticism, insulting comments, and conflicting claims and counterclaims. For the average consumer, separating reputable sources from propaganda is tough, if not impossible.

In 2017, researchers with Michigan State University’s Food@MSU initiative conducted the first nationwide Food Literacy and Engagement Poll. They asked more than 1,000 consumers about their knowledge of and opinions related to our food system, and of the science behind it.

When asked whether they thought the statement “Genetically modified foods have genes and non-genetically modified foods do not,” was true or false, 37 percent of respondents said they believed it was true. In fact, all food contains genes. The average plant, for example, has 20,000 to 45,000 genes, while humans have about 20,000 genes (according to a 2014 article in The Scientist magazine).

Respondents were also asked to rate how much they trust scientists when it comes to the health and safety of food. Academic scientists fared best, earning the trust of 59 percent of respondents, with governmental scientists in the middle at 49 percent and industry scientists trusted by only 33 percent.

In a 2016 Pew Research Center survey of more than 1,400 U.S. adults, 39 percent of respondents reported that they believe genetically modified foods are worse for health than non-GM foods, 10 percent indicated that GM foods are better for health than non-GM foods; and 48 percent responded that GM foods were neither better nor worse for health than non-GM foods. This indicates that a significant portion of the public is either neutral on the issue of GM foods or doesn’t know what to think. This result is somewhat surprising, given that media reports often indicate that no one is undecided about the GMO controversy.

What is a GMO?

Even the answer to the question “What is a GMO?” can be controversial.

At its most basic, genetic modification is the process by which changes occur in an organism’s genome. Nature is perpetually modifying the genetics of every organism in an effort to help the organism adapt to its changing environment.

“It’s important to understand that all organisms — not just those that are the basis of foods — are genetically modified in some way, shape or form,” said Brad Day, a professor and associate department chair for research in the MSU Department of Plant, Soil and Microbial Sciences. “They are genetically modified by persisting in the environment. Radiation from the sun can induce changes in the genome, for example.”

More than 30,000 years ago, humans realized they could have a hand in the process of modifying genes when they domesticated and began selectively breeding wolves to ensure the animals passed along specific characteristics (such as docility, fur color, tracking ability, size or protectiveness). This practice set the stage for contemporary dog breeding. Humans have bred plants for thousands of years, too, in an effort to ensure the survival of desirable traits.

While conventional selective breeding methods are still the most common, the newer biotechnology techniques used to create GMOs are actually rooted in genetic engineering. Scientists use biotechnology to insert one or more genes from one organism into another to give the second organism the specific trait controlled by the transferred gene or genes.

Adding a gene that promotes drought resistance, for instance, may permit farmers to grow a crop in a nontraditional region of the world or in an area with dwindling water resources.

In 1973, Herbert Boyer and Stanley Cohen created the first genetically engineered organism – E. coli bacteria that had the gene for resistance to the antibiotic tetracycline transferred into it. Once the pair demonstrated that the organisms could pass the added trait to subsequent generations, interest in genetic engineering ballooned.

Farmers who became early adopters of GM crops did so primarily to save money. Insect-resistant crops needed fewer pesticide applications, and herbicide-resistant crops made weed control easier and more effective.

“Genetic engineering is a technology used in several disciplines, but food has been by far the most controversial [use],” Day said. “Changes in the genome may include input traits – something that helps the grower manage the crop better in response to insects, diseases or weeds. There are also output traits – things that might improve yield, delay flowering times or enhance a plant’s ability to produce a nutritional element such as a vitamin.”

Today, GM varieties of 10 crops have been approved for sale by the federal government and are commercially available in the U.S. Corn, soybeans and cotton represent the vast majority, and roughly 90 percent of those crops produced in the U.S. are GM varieties. The other approved GMO crops are varieties of squash, papaya, alfalfa, sugar beets, canola, the Innate potato and the Arctic apple.

Three federal agencies are responsible for approving GMOs, depending on the organisms’ intended purpose: the U.S. Department of Agriculture, the U.S. Environmental Protection Agency, and the U.S. Food and Drug Administration.

Are GMOs safe?

The most debated topic related to GMOs is whether they threaten the health of humans or the environment. Critics often call GMOs “unnatural” and “dangerous.” Researchers such as Rebecca Grumet, a professor in the MSU Department of Horticulture, point out that safety questions can also arise with conventional breeding, since plants make toxic substances on their own.

“Modification through genetic engineering is not unsafe simply because it’s genetic engineering,” Grumet said. “In terms of alterations to a plant’s genome, what’s important is not the method that was used. It’s what genes or traits have been introduced. The idea behind genetic engineering is that it’s more precise, and it lets scientists take advantage of traits present in a given species to better another.”

Internationally renowned organizations (such as the American Medical Association, the National Academy of Sciences and the World Health Organization) have deemed GMOs safe. Rigorous testing throughout the process of trait development, and ensuing research, have led scientists to reach the same conclusion.

“Hundreds of independent research studies have shown that there are not greater risks associated with GM crops,” Grumet said. “There is scientific consensus on this topic, despite the controversy.”

According to the Genetic Literacy Project (GLP), it takes an average of eight years and more than $135 million to develop a new GM trait and shepherd it through the federal regulatory process. The GLP is a part of the Science Literacy Project, a nonprofit organization funded by grants from foundations and charities that accepts no corporate money.

The best-known GMOs are probably the Roundup Ready crops that are resistant to glyphosate, the active ingredient in the herbicide Roundup. Introducing a resistance gene into a crop’s genome allows farmers to better control weeds without causing unintentional harm to crops.

A common criticism of glyphosate-resistant crops is that their existence has encouraged the skyrocketing use of Roundup over the past two decades, which could harm human and environmental health. Grumet, who co-teaches an MSU class called “Biotechnology in Agriculture: Applications and Ethical Issues,” sees that criticism as misleading.

“It’s certainly true that there has been a drastic increase in the use of Roundup, but there has been a parallel decrease in the use of other herbicides,” Grumet said. “Much of the time, the herbicides farmers used historically were far more toxic than Roundup, which is one of the least toxic.”

Given the pervasiveness of Roundup Ready crops, glyphosate-resistant weeds are becoming a problem in the environment, and in some cases, leading to a return to the use of the older herbicides Grumet mentioned.

She said that this is not surprising. When used frequently (as is the case with antibiotics) any product will lead to the natural survival – and therefore selection – of individuals that are resistant to the product. (One example is the development of antibiotic-resistant bacteria.) This is why agricultural scientists must continually search for new ways to manage emerging threats to crops. Keeping consumers informed of disease and pest problems in food crops and about the science behind potential solutions to these problems helps increase public understanding and acceptance.

“We, as scientists, must do a better job of interacting with the public about this topic,” Day said. “Roundup Ready crops are a really good example. I don’t have a vested interest in touting GMO technology as a catchall answer to solving the problem of world hunger. It’s one tool among many that society has to understand in order for the technology to be deployed in the most efficient, safe and useful way possible.”

Are GMOs necessary?

Conservative estimates suggest that the human population will surpass 9 billion by 2050. The actual figure could be closer to 10 billion. Either way, we’ll need a massive boost in food production to feed that many people. Crops that are more adaptable to varying climate conditions and less vulnerable to pathogens and other pests will be significant pieces of the puzzle.

“We can’t control the fact that the population is increasing or that there is a finite amount of agricultural land – land that is decreasing in quality overall,” Day said. “When you’re talking about feeding 9 or 10 billion people by 2050 with crops that won’t get wiped out by pests and diseases, we don’t have the luxury of feeding everyone from a backyard garden. Some people have fears about large-scale industrial agriculture and GMOs, and that’s why we should also be looking at things from the viewpoint of sustainability.”

Wealthier families currently have greater ability to decide on whether to consume GM foods or not. Additionally, regulatory systems in the U.S. make introducing GM foods an expensive and onerous process designed to protect consumers. In other communities, especially those around the globe facing matters of basic nutrition and sustenance, choices are much more limited.

Cholani Weebadde, an assistant professor in the MSU Department of Plant, Soil and Microbial Sciences and associate director of the World Technology Access Program, spends much of her time assisting developing countries with capacity building. A plant breeder and international agriculture expert, Weebadde is uniquely suited to speak about GMOs with political and agency leaders.

“In my opinion, it’s important that countries have functional regulatory systems in place so they can make science-based, informed decisions on commercializing GM crops and products so farmers have access to the best technologies,” Weebadde said. “Having transparent systems in place with evaluations conducted using a risk-based approach – is important for countries and their ability to say yes or no to the technologies.”

In Uganda, for example, bananas are a staple crop that is highly susceptible to a pathogen that causes bacterial wilt. Plant breeders have tried to use conventional selective breeding techniques on elite banana selections to bolster resistance to the disease, but the trait doesn’t seem to exist in the banana genome.

Scientists observed, however, that another food crop, sweet pepper, has two genes that could do the trick. By inserting the appropriate genes from sweet peppers into bananas, they were able to develop bananas that are resistant to bacterial wilt. But because Uganda doesn’t have an efficient process for approving genetically modified crops, these bananas can’t be grown commercially in the country.

Pests and diseases aren’t the only concerns driving the development and use of genetically modified crops. Climate change is also making farming more challenging worldwide. According to Weebadde, some food crops are naturally ill-equipped to handle the added environmental stresses, ranging from not enough rain to unyielding cold spells.

“Since we are dealing with narrow genetic and germplasm bases for most of our staple food crops, we may have to reach out to genetic engineering technologies and genes from other sources to improve them further,” she said. “Otherwise, we may run out of options.”

Golden rice is a well-known case in which GMO development has stalled due to lack of regulation. Pioneered throughout the 1990s, golden rice was developed to combat vitamin A deficiency in countries that rely on rice as a staple crop. Lack of vitamin A can lead to blindness and even death.

Three genes help golden rice produce beta carotene, which the human body synthesizes into vitamin A. Critics said the initial product didn’t generate enough beta carotene to make an appreciable difference. A second version unveiled in 2005, however, contained 23-times more of the substance than the original.

Some organizations in the U.S. and Europe have rallied against golden rice commercialization. Weebadde believes that policy makers at the country level should be empowered, through the establishment of regulatory bodies, to make decisions on behalf of their citizens.

“We don’t need to think as much about issues such as vitamin A deficiency in the U.S. because it’s well under control,” Weebadde said. “But we wield a lot of power in terms of developing regulatory processes for GMOs. It’s our responsibility to provide all of the facts as they are.

“Although some issues may not be a concern in the U.S., oftentimes our actions can have deleterious effects internationally, so we have to be responsible for those actions. Providing unbiased, science-based information regarding GMOs is crucial for this reason.”

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