Students explore the process of genetic engineering and discover the eleven bioengineered crops and two animals approved in the United States. Grades 3-5

agrobacterium: a type of bacteria that lives naturally in the soil and has a unique ability to transfer its DNA to plants

bacteria: a group of single-celled living things that cannot be seen without a microscope that reproduce rapidly and sometimes cause diseases

bioengineering: biological techniques including things such as genetic recombination to created modified versions of organisms

biotechnology: the use of living systems and organisms to develop or modify products or processes

deoxyribonucleic acid (DNA): deoxyribonucleic acid; a self-replicating material present in nearly all living organisms as the main constituent of chromosomes; the carrier of genetic information

disease: a particular abnormal condition that negatively affects the structure or function of all or part of an organism

fertilizer: any material of natural or synthetic origin that is applied to soils or plant tissues to supply one or more nutrients essential to plant growth

food additive: a substance added to food to enhance its flavor or appearance or to preserve it

gene: a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring

genetic engineering: the process of directly modifying an organism's genes using biotechnology to produce desired traits

genetically modified (GM): an organism or crop containing genetic material that has been artificially altered so as to produce a desired characteristic

genetically modified organism (GMO): any organism whose genetic material has been altered using genetic engineering techniques

greenhouse gas: a gas that contributes to the greenhouse effect by absorbing infrared radiation

herbicide: a substance that is toxic to plants and is used to kill unwanted vegetation

organic: term used to classify farming methods that limit the use of some common practices such as biotechnology and types of fertilizer or pesticide

pesticide: a chemical that is used to control an organism living and growing where it is not wanted

resistant: not affected or harmed by something

soil tillage: turning the soil to control for weeds and pests and to prepare for seeding

sustainability: a method of harvesting or using resources so that they are not depleted and/or permanently damaged

tolerant: ability of a plant or animal to endure

trait: observable, physical characteristic obtained through genetic inheritance

transgenic: containing a gene that has been transferred from one organism to another and acts as a synonym for genetically modified

There are many terms and acronyms used to describe genetically modified organisms or biotechnologies. Genetically engineered (GE), genetically modified (GM), bioengineered, genetically modified organism (GMO), and transgenic are all adjectives used to describe an organism that has a copy of a gene not previously found in the species. The BE Disclosure law went into effect in January 2022 and uses "bioengineered" as the term of choice for these products of biotechnology. Throughout the lesson, determine the terminology students are familiar with and provide clarification to prevent misconceptions.

Farmers face risks everyday—weather extremes, pests, and other factors that can negatively affect a plant growing in a field. Drought, flooding, hail, wind, frost, heat, weed population, insect infestations, disease outbreaks, and numerous other elements can adversely impact food production. Despite all that can go wrong, grocery store shelves are stocked and livestock are well fed. Farmers are able to grow usable crops all the way to completion. How is this possible? How are farmers today able to use less land and grow 430% more corn than was grown in 1950?¹ The answer is science, technology, and the ability to harness and apply new ideas and discoveries to improve crop resiliency. Genetic engineering is a development that has majorly impacted agriculture.

Genetic engineering is the deliberate modification of the characteristics of an organism by manipulating its genetic material. The Rainbow papaya is an example of a plant that has been genetically engineered. In the 1990s, the papaya ringspot virus had nearly wiped out the entire papaya industry on the island of Hawaii. However, a scientist named Dennis Gonsalves engineered a papaya tree to be resistant to the virus and provided hope and sustainability to papaya producers who were facing the loss of their livelihood.² Along with papaya, other GE crops that are on the market as of 2023 in the United States include corn (field and sweet), cotton, canola, apples, alfalfa, potatoes, pink pineapple, soybeans, summer squash, and sugar beets. Each crop was engineered for different reasons, including drought tolerance, herbicide tolerance, insect resistance, disease resistance, and non-browning ability. Along with protecting the livelihoods of farmers, GE can benefit the environment due to less pesticide use, less soil tillage, and less greenhouse gas emissions.

Corn: Most of the corn grown in the United States is genetically engineered to resist insect pests or tolerate herbicides. Bacillus thuringiensis (Bt) corn is GMO corn that produces proteins toxic to certain insect pests but not to humans, pets, livestock, beneficial insects (such as ladybugs), or other animals.⁴ Some genetically modified corn in used in processed foods and drinks, but most is used in livestock feed.

Canola: Most genetically engineered canola is resistant to herbicides, allowing farmers to use herbicide sprays to control weeds in their fields. GMO canola is used to make cooking oil, margerine, and canola seed meal for animal food.

Cotton: Genetically engineered cotton is resistant to bollworms. GMO cotton is used in the textile industry, to make cottonseed oil (used in packaged foods and for frying), and animal feed.

Apple: GMO apples are resistant to browning after being cut.

Alfalfa: Most genetically engineered alfalfa is resistant to herbicides. GMO alfalfa is used to feed cattle, primarily dairy cows.

Papaya: A GMO papaya, named the Rainbow papaya, is resistant to the ringspot virus. 

Potato: Some genetically engineered potatoes are resistant to insect pests and disease. Other GMO potato varieties are resistant to bruising and browning.

Pink Pineapple: The GMO pink pineapple is sweeter than other varieties and has pink flesh because of the increased levels of lycopene, a pigment naturally found in pineapples.

Soybean: Most of the soybeans grown in the United States are genetically modified. Some GMO soybean varieties are resistant to herbicides, some varieties are tolerant of abiotic stress such as drought or hypersaline conditions, some varieties are resistant to pests, and some varieties are resistant to soy oil rancidity. Most GMO soybeans are used for soybean oil, in processed foods, and animal feed.

Sugarbeet: Genetically engineered sugar beets are resistant to herbicides. More than half of the granulated sugar in grocery stores is made from GMO sugar beets.

Summer Squash: GMO summer squash are resistant to some plant viruses. 

There are currently two GMO animals in the food supply, the AquAdvantage Salmon and the GalSafe pig. The FDA has determined that these animals are as safe and nutritious to eat as food from non-GMO salmon and pigs.⁴

Salmon: AquAdvantage salmon has been genetically modified to grow faster than other salmon varieties.

Pig: The GalSafe pig has been genetically modified to be free of alpha-gal sugar. People who have allergic reactions to alpha-gal sugar (Alpha-gal syndrome) can safely eat meat from Gal-safe pigs.

To learn more about GMO crops and animals in the United States, see the U.S. Food & Drug Administration (FDA) article GMO Crops, Animal Food, and Beyond.

The process of genetically engineering a plant has four main steps—identifying the problem, finding the solution, inserting the desired gene, and growing the engineered plant. Identifying the problem that needs to be solved for a specific crop is the most straightforward step. In the case of the papaya, the problem was the ringspot virus. After identifying the problem, scientists search for the specific gene sequence that expresses the desired trait. When insect-resistant corn was being developed, scientists found the desired gene sequence in the Bacillus thuringiensis (Bt) bacteria. Once the desired gene is found, it needs to be inserted into the plant. Originally, this was accomplished by a machine called the gene gun, which bombarded plant tissue with microscopic pieces of gold covered with millions of copies of the desired gene; however, the method used today is far more advanced and precise. Scientists genetically engineer plants through agrobacterium. Agrobacterium is a bacteria found naturally in soil. It infects wounded plants and inserts a portion of its own DNA into the plant's DNA, forcing the plant to create food for the bacteria and killing the plant. Scientists used this knowledge and were able to engineer the bacteria to insert one special gene, such as the Bt gene in corn, in place of the bacteria of the gene that kills the plant. Finally, the plant is grown in order to determine if the desired trait is expressed and to test for possible consumer health and environmental impacts. 

Genetically Modified Organism (GMO) is the broad term for any organism that has undergone the process of genetic engineering. GMOs go through an extensive testing process that lasts many years. Testing is implemented by the Environmental Protection Agency (EPA), the Food and Drug Administration (FDA), and the United States Department of Agriculture (USDA). Once all regulatory processes are complete, the plant or animal can be approved for commercial use. Scientists and the majority of health organizations around the world agree that GMO foods are safe for human and animal consumption.³

Consumers who prefer not to eat GMOs have options. In recent years, some agricultural producers have made the decision to produce organic food which is grown without the aid of synthetic pesticides or chemical fertilizers, and produced without the use of genetically modified organisms or chemical food additives.

1. Project slide 1 of the Do You Know GMO? slideshow. Ask the students to raise their hand if they have ever heard of a GMO. Ask, "What does GMO stand for?"
2. Show slide 2 and explain that GMO stands for Genetically Modified Organism.
3. Show slide 3 and ask the students to raise their hand if they have seen labels like these before. Ask, "What do these labels mean?" (Manufacturers sometimes put these labels on their products to show that the food has been genetically engineered.)
4. Show slide 4 and ask students to raise their hand if they have heard of genetic engineering. Ask, "Did you know scientists can change the genes in a plant?" 
5. Explain to the students that they will be exploring DNA so that they can better understand genetic engineering.

Teach with Clarity There are many terms and acronyms used to describe genetically modified organisms or biotechnologies. Genetically engineered (GE), genetically modified (GM), bioengineered, GMO, and transgenic are all adjectives used to describe an organism that has a copy of a gene not previously found in the species. The BE Disclosure law went into effect in January 2022 and uses "bioengineered" as the term of choice for these products of biotechnology. Throughout the lesson, determine the terminology students are familiar with and provide clarification to prevent misconceptions.

 

1. Project slide 5 of the Do You Know GMO? PowerPoint. Explain to the students that in order to understand genetic engineering, they must first know what DNA is. Lead a discussion about DNA. Include the following points in the discussion:
   • DNA stands for deoxyribonucleic acid.
   • DNA is the building block of all living organisms.
   • DNA gives each living organism its own unique traits and characteristics.
   • Traits are found in sections of DNA called genes.
2. Show slide 6 and play the DNA Sam Animation.
3. Show slide 7. Choose four students to come to the front of the room and assign them each a Corn Borer Worm Activity Picture with the Corn Borer Worm Skit attached to the back of each picture. Explain that the two corn kernel images represent two corn genes, the worm represents the corn borer worm, and the Bt gene represents one gene from the Bt bacteria that is resistant to the corn borer worm.
4. Have the corn genes stand together on one side of the room, the Bt gene stand on the opposite side of the room, and the corn borer worm stand next to the corn.
5. Have the students read the skit to demonstrate how corn was genetically modified:
   • Corn borer worm: The corn borer worm is a real problem farmers face today. (Point to the picture on the screen.) As you can see by the picture, the corn borer worm destroys corn.
   • Corn genes: Scientists were able to help farmers by genetically engineering corn. 
   • Bt gene: Scientists found a gene in Bt bacteria that the corn borer worm does not like. (Move in between the two corn genes.) The scientists moved that special gene into the corn's DNA.
   • Corn borer worm: (Move away from the two corn genes with fear.)
   • Corn genes: Now that the Bt gene is in the corn, the corn is resistant to the corn borer worm. 
6. Have the students return to their seats and show slide 8. Explain that moving genes is not as easy as what just happened in the skit. Real genes are microscopic. We will look at two methods of genetic engineering.
7. Show slide 9 and explain that the first method scientists used to genetically engineer plants is the gene gun. The gene gun is an amazing machine that shoots microscopic pieces of gold covered with billions and billions of copies of the one special gene into a plant cell with hopes that one of those copies will insert itself into the plant's DNA. The gold dissolves quickly and does not affect the plant cell.
8. Show slide 10 and explain that another way scientists genetically engineer plants is through agrobacterium. Agrobacterium is a bacteria found naturally in soil. It infects wounded plants and inserts a portion of its own DNA into the plant's DNA, forcing the plant to create food for the bacteria and killing the plant. Scientists used this knowledge and were able to engineer the bacteria to insert one special gene, such as the Bt gene in corn, in place of the bacteria of the gene that kills the plant.
9. Show slide 11 and explain that there are eleven genetically engineered crops approved in the United States.
10. Show slide 12 and have ten students each read one of the eleven GMO (bioengineered) crops. Explain that an easy way to remember the eleven crops is by remembering the word C₃A₂P₃S₃.
    • C₃ = Corn, Cotton, Canola
    • A₂ = Apples, Alfalfa
    • P₃ = Potato, Papaya, Pink Pineapple
    • S₃ = Soybeans, Summer Squash, Sugarbeets
11. Show slides 13-23 and explain what problem each crop is bioengineered to overcome. As appropriate, ask the following questions:
    • Have you ever eaten this crop?
    • What do we use this crop for?
    • What can be made with this crop?
12. Show slide 24 and explain that there are two genetically engineered animals approved in the United States—salmon and pigs. Show slides 25 and 26 and describe the problems each animal is bioengineered to overcome.
13. Have the students either draw one of the ten crops using the Draw a Crop activity sheet or build a 3-D model of an apple, corn, cotton, canola, or a potato by following the Build a Crop Instructions.

Many seed varieties are available to farmers. Just because there is a GMO seed variety available (as in the case of corn, cotton, canola, apples, alfalfa, potato, papaya, soybeans, summer squash, and sugarbeets), it does not mean that all farmers grow the GMO variety. Farmers select plant varieties to meet the needs of their farm. In some cases it might be a GM variety, and in other cases it will not.

 

1. Show slides 27-41 and ask students the questions on the slides to review what they learned. Click to the following slide to reveal the answer.
2. Provide each student with the Do You Know GMO? Handout.

1. https://www.farmprogress.com/equipment/eight-major-factors-have-changed-agriculture-last-50-years
2. https://foodinsight.org/how-gmo-technology-saved-the-papaya/
3. https://www.forbes.com/sites/jonentine/2014/09/17/the-debate-about-gmo-safety-is-over-thanks-to-a-new-trillion-meal-study/#19b243288a63
4. https://www.fda.gov/food/agricultural-biotechnology/gmo-crops-animal-food-and-beyond