NC State Extension

Frequently Asked Questions (FAQs) to NCSU County Faculty

Q1:  What is the difference between genetically modified organisms and genetically engineered organisms. (We seem to use the terms interchangeably)

A: Good question. Here is a rather short answer to this question from NAS: FAQs on GE Crops | Genetically Engineered Crops at the National Academy of Sciences

Genetically engineered and genetically modified are often used interchangeably when referring to varieties of crops developed by means other than traditional breeding. Genetic modification refers to a range of methods (such as selection, hybridization, and induced mutation) used to alter the genetic composition of domesticated plants and animals to achieve a desired result. Genetic engineering is one type of genetic modification that involves the intentional introduction of a targeted change in a plant, animal, or microbial gene sequence to achieve a specific result.

Now for a little more detailed answer. Scientists originally never used the term genetically modified organisms or GMOs to describe genetic engineering. This term seems to have come from the popular media. The term has become so common that even scientists often use the term now. For many the terms genetically modified organisms are synonymous with genetically engineered organisms.

Most scientists would say that almost all the food we eat has been “genetically modified” by man and that genetic modification includes not only conventional breeding, but simple selections man has made over millennia. Carrots were not orange until the 1700’s and tomatoes used to be the size of marbles. Corn used to have very small ears and had kernels with hard seed coats and low digestibility. See picture below from NSF.

corn-and-teosinte_h1

Genetically modified food would include almost all the food we eat. Several different way plant genomes are altered “conventionally” and via genetic engineering are described here. Genetically engineering is the direct manipulation of an organism’s genome using biotechnology. Although many people think this means moving genes from one species to another, that is not always the case. There are several biotechnological methods of manipulating genes. Sometime this is done by actually moving genes within a species or from a closely related species. This resulting organism is referred to as cisgenic. Gene editing is another method of manipulating DNA. There are several techniques available for gene editing including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the clustered regularly interspersed short palindromic repeats (CRISPR)/Cas systems. Gene editing may involve deletion, insertion, silencing or repression. The resulting organism from gene editing is called subgenic.

The type of genetic engineering that the public is most likely familiar with is transgenic. This is where a gene is moved from one non-closely related species to another. Cisgenic changes to DNA would also be possible through conventional breeding, while transgenic changes to DNA are not possible via conventional breeding.

Keith Edmisten, Professor of Crop Science

Q2:  What crops have a GMO trait? What do the (these) traits do? What is the benefit of these traits?

There are 8 commercially available genetically engineered (GE) crops in the US. They are alfalfa, canola, corn, cotton, papaya, soy, squash, and sugar beets. A potato and apple have been approved but are not commercially available at this point. Genetically engineered insect resistant brinjal is currently approved and grown in Pakistan. Brinjal is what we call eggplant in the US.

The traits that are currently available include herbicide tolerance, insect tolerance and disease tolerance. There are also crops that have been developed that improve nutritive value of foods, some of which are close to being commercialized. Who benefits is mostly related to the trait rather than the crop so I will discuss the benefits and who benefits based on the traits.You could break down who benefits into benefits for the consumer, environment, farmer, and the needy. Technologies that benefit the environment would be thought to beneficial to the general public as well.

Herbicide tolerance is often seen as only beneficial to the farmer. However, herbicide tolerance, in particular Roundup (glyphosate) tolerance, has led to an increase in reduced tillage. Reduced erosion is a benefit to the environment and to the public. Reduced tillage systems with herbicide tolerant crops also lead to reduced fuel use on farms. This is definitely a benefit to the environment.

Herbicide tolerance is often said to have increased herbicide use due to herbicide resistance. Herbicide resistant weeds are often referred to as  “superweeds”. Weed resistance is not unique to farming genetic engineered (GE) crops. Farmers have had problems with weed resistance to herbicides before genetically engineered crops were available. In fact, the number of newly identified herbicide resistant weeds per year has slowed down since the adoption of GE herbicide tolerant crops.

The often reported increase in herbicide use due to GE crops is not as simple as it might appear. The total amounts of herbicides decreased during the first years of GE crop production and then has increased almost to levels prior to GE cropping due where herbicide resistant weeds have appeared. What has changed is the environmental impact. Cornell developed an environmental impact quotient that includes dermal toxicity, chronic toxicity,  systemicity,  fish toxicity, leaching potential, surface loss potential, bird toxicity, soil half-life,  bee toxicity, beneficial arthropod toxicity, plant surface half-life. GE crop herbicides systems have a lower impact on the environment based on these calculations.

Genetic engineering is not the only way that herbicide tolerant crops have been produced. Mutation breeding has been used to create commercially available herbicide tolerant crops that are not subject to the regulations and testing that are required for GE herbicide tolerant crops.

Insect tolerant GE crops have led to reduced insecticide use. Corn and cotton are crops that have been genetically engineered for insect tolerance in the US. This technology is certainly a benefit for the farmer due to reduced insecticide applications. Reduced insecticide use benefits the environment because of lower impacts of farming on non-target species such as bees, beneficial insects and fish. Insect tolerant crops are also especially beneficial to farmers in developing countries who have less access to insecticides and often the only insecticides they have access to are more toxic older insecticides. These farmers often spray by hand and do not have proper safety equipment to handle or apply pesticides safely.

Papaya is the only commercially available GE crop that has been engineered for virus resistance. This technology saved the papaya industry in Hawaii. This technology benefits the environment as insecticide sprays are not need to control insects that vector the virus. The availability of papaya is a benefit to the consumer. Virus resistance has already been engineered for plums and is ready if plum pox virus becomes more serious. Scientist are working on engineering resistance to diseases in other crops like bananas, grapes and citrus. Citrus greening is a virus that is a serious threat to the citrus industry in Florida and in other parts of the world. Like with papaya, the use of genetic engineering could help save the industry. Currently the only methods of control are removing diseased trees and spraying insecticides in an attempt to limit the spread of the disease. These efforts have not been very successful. GE citrus crops may benefit the consumer by keeping citrus available in markets and benefit the environment by reducing insecticide applications.

A GE blight resistant potato (Fortuna) has been developed but has not been commercialized due to fears about consumer acceptance. Blight is what caused the Irish potato famine. Blight still is a major pest in potatoes. A blight resistant potato would benefit the environment by reducing fungicide applications.

Bananas are under threat from several diseases and there is current research developing GE disease resistant bananas. Bananas make up a large portion of the diet of some African countries. Conventional breeding for disease resistance in asexually propagated crops like bananas is difficult.

Both apples (Arctic apples) and potatoes (Innate potatoes) have been genetically engineered so that they do not brown when cut open. The potato also reduces acrylamide in potatoes. Acrylamide has been linked to some cancers. Both products could benefit consumers by reducing food waste. The small company that produced Arctic apples hopes the ability to serve sliced apples that do not brown will increase apple comsumption by children.

Another category of GE crop traits is improved nutritional content or health benefits. Examples are purple tomatoes and pink grapefruit with increased levels of antioxidants and golden rice which is engineered to reduce vitamin A deficiency. These crops are not available at this time but could be available in the near future. Golden rice would be beneficial to the needy in developing countries. About 500,000 people go blind every year due to vitamin A deficiency. About half of those die within a year due to other complications related to vitamin A deficiency. There is also active research utilizing genetic engineering to reduce allergens in such foods and peanuts and rice.

The final category is traits for industrial processes. Two examples would be Amflora potato and Enogen corn. Amflora potato was engineered to have reduced levels of amylose to make it more conducive to some industrial applications like paper making. Enogen corn contains a transgene from a bacteria that produces alpha amylase, an enzyme that breaks down corn starch into sugar. Enogen corn can be used to make ethanol with less energy and water than conventional corn. That would be an environmental benefit.

One GE food product that is rarely mentioned is cheese. Over 90% of the cheese is made using genetically engineered microbes rather than calf stomachs (rennet).

One can see that each trait is different and that each trait may benefit different different parts of society, and in many cases a trait has more than one beneficial attribute.

Keith Edmisten, Professor of Crop Science

Q3:  How long has the health benefit/risk of GMO in our foods been studied? Are there any long-term studies examining the effects of GMO products on humans?

Of course we have been eating GE food for almost 2 decades with no reports of health problems, but that is not a study. GE crops are the most studied foods in the history of man. There have been over 2000 studies conducted on GE foods. How many are long term? That of course depends on what you consider long term. Ninety days is generally considered sufficient in order to evaluate the health effects of GM feed. There have been longer studies, some multi-generation studies. Here is a paper that reviews long term studies on the health impact of GM plants.

Assessment of the health impact of GM plant diets in long-term and multigenerational animal feeding trials: A literature review

GENERA maintains a list of many of the studies conducted on GE crops. You can find the list here. There is also a search function if you would like to narrow down the list.

Many scientists find it ironic that there is so much health related studies of GE crops. No other form of plant breeding requires testing. Crops created using chemically or radiologically induced mutations require no testing even though this technique is much less precise than genetic engineering. Mutation and other forms of plant breeding change much more DNA and have a less known genetic outcome than genetically engineered crops.

Keith Edmisten, Professor of Crop Science

Q4:  Why are all the GMO traits aimed at increasing production rather than adding value to nutrition of foods or other health benefits.

You could certainly argue that insect resistance not only increases production, but also reduced insecticide applications. Many people would consider reduced insecticide applications a potential health benefit. You could also argue that herbicide tolerance has led to an increase in reduced tillage which reduces CO2 emissions and soil erosion. Maybe those are not direct health benefits, but you could argue that they are beneficial to society.

But your point is a good one, most of the GE crop acreage is devoted to technology that many see as more beneficial to the farmer than the consumer. Is there any other industry that receives that type of criticism? If Apple makes functional improvements to their phone production that might  make the phone easier or cheaper to produce, do we protest against those improvements just because we may not see them when the final product is in our hand?

The response to question 2 gives some details about who benefits from various GE crop technologies. Some of the technologies listed that have direct consumer benefits have been developed, but not commercialized. That is because it is expensive to go through the regulatory process. Products do not only have to go through the US regulatory process, they have to go through regulatory processes throughout the world. This is very expensive and is part of the reason that most of the technologies that companies have been willing to invest in are technologies that farmers are willing to pay for. Most people think only large corporations are involved in developing GE crops. About half of the activity is actually in public sector and small firms. Much of the work on improved nutrition and health benefits have been conducted in the public sector and small firms that do not have the resources to pursue the regulatory process as aggressively. The fear of lack consumer acceptance of GE crops is a another deterrent to developing GE crops that benefit the consumer. Most of the GE crops are used for purposes that do not involve direct consumption of proteins by humans.

There seems to be a current trend towards increasing research in GE crops with consumer benefit. As the science advances, consumer confidence rises and the regulatory process becomes more stable across the world, we should see more of these consumer related technologies become commercialized.

Keith Edmisten, Professor of Crop Science

Q5: Are GMO crops regulated and if so, by whom?

Yes, they are regulated. GE crops are regulated under 3 agencies in the US. Each of these agencies regulates GE crops from a different perspective and a crop may fall under more than one agencies for regulation. This process is called the Coordinated Framework for Regulation of Biotechnology.

USDA is involved from a plant pest viewpoint. This includes concerns that the GE crop might cross with a wild relative. USDA is also involved concerning plant pests used in the transformation process or is the contributor of any part of the gene construct. Examples would be the use of the 35S promoter which was derived from cauliflower mosiac virus and the use of agrobacterium in the transformation process.

EPA regulates any GE crop that are pesticide related. This would include GE crops that produce biopesticides like Bt insect resistant crops. They also have to approve any pesticide tolerances, such as herbicides involved in herbicide tolerant GE crops.

FDA reviews the information provided by the company, university or public entity to determine if the GE crop is “substantially equivalent” to its conventional counterpart. This step is not currently mandatory and is called a consultative process. To date all entities have provided these data. There is currently legislation in congress that would make this process mandatory. Companies and other GE crop producing entities have supported this measure as they are already providing these data.

GE crops produced by large companies on crops grown worldwide also have to satisfy the regulatory system of not only the countries they would like to sell seed in, but also the countries that might import GE agricultural crops for human or animal consumption. This process is very expensive and is not required for any other crop development method, including mutation breeding using chemical or radioactive mutagens.

The chart below illustrates how expensive it is to develop a GE crop and how much of the expense goes to satisfy the regulatory process. These data are from a study conducted by CropLife in 2011.

cost of developing GMO

More detailed information about GE crop regulation is available here.

Keith Edmisten, Professor of Crop Science

Written By

Photo of Keith Edmisten, N.C. Cooperative ExtensionDr. Keith EdmistenProfessor of Crop Science & Extension Cotton Specialist (919) 515-4069 keith_edmisten@ncsu.eduCrop and Soil Sciences - NC State University
Page Last Updated: 3 years ago
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