Exploring Careers: Genetic Engineering (Grades 9-12)

OK, so genetic engineers aren't at the point where they can make pills and capsules grow in place of corn kernels, but scientists have engineered corn and other plants (as well as animals) to produce pharmaceuticals. In the Connections section, you can read more about this work and the controversy that surrounds it--particularly when crop plants like corn are involved. [Image courtesy of The Pew Initiative on Food and Biotechnology]

National Engineers Week, February 20-26

Engineering is the art of applying scientific and mathematical principles, experience, judgment, and common sense to create or develop new products that benefit people and solve problems. Engineers search for better, less expensive ways to use the forces and materials of nature to meet tough challenges as people encounter them. There are many fields of work within engineering; one of the newer--and growing--branches is genetic engineering.

What exactly is genetic engineering? Is it really something different from the domestication and breeding of plants and animals that humans have done through the ages? Who does this work? The answers to these questions are not as easy as you might think.

We have chosen here to define genetic engineering in the spirit of the Food and Agriculture Organization (FAO) of the United Nations and the U.S. Department of Energy. The FAO defines it as: "Changes in the genetic constitution of cells (apart from selective breeding) resulting from the introduction or elimination of specific genes through modern molecular biology techniques. This technology is based on the use of a vector for transferring useful genetic information from a donor organism into a cell or organism that does not possess it." The FAO goes on to say that "a broader definition of genetic engineering also includes selective breeding and other means of artificial selection."¹ We're going to stick with the more focused definition versus the broad one, but as you can see, there are different ways to draw the boundaries around what is and is not genetic engineering. We also draw on the Department of Energy's definition: "Altering the genetic material of cells or organisms to enable them to make new substances or perform new functions,"² because it addresses why genetic engineering is done.

So, for our purposes, in genetic engineering, scientists use molecular techniques to deliberately alter the DNA sequence of cells or organisms for a specific purpose. The gene that's engineered (transferred) into an organism is called a transgene, and the organism, be it a bacterium or a corn plant, that now has a new genotype is often called a transgenic organism, a genetically engineered organism (GEO), or a genetically modified organism (GMO). Currently researchers are designing GEOs for a variety of potential applications in areas like agriculture, medicine, industry, environmental remediation, and scientific research.

It's not uncommon for people to equate biotechnology with genetic engineering. But biotechnology is bigger than just genetic engineering. Biotechnology broadly includes practices begun in ancient times such as cheese- and bread-making and countless later advances like the widespread production of penicillin begun in the World War II era. Adding to the confusion surrounding what is and is not genetic engineering, modern efforts like gene mapping and sequencing (think Human Genome Project), the genetic screening of newborns, DNA fingerprinting, and the cloning of mammals (think Dolly the sheep) use some of the same techniques as genetic engineering and vice versa. But the goal of these efforts (at least for now) is not to create an organism with a novel genetic makeup.

Going back to the who question in the first paragraph, it's entirely possible (even probable) that a person who genetically engineers organisms is not called a genetic engineer. Here are just a few of the job titles that such a person might have: molecular biologist, plant biotechnologist, molecular geneticist, bioengineer or biological engineer or biomedical engineer, food scientist, laboratory technician, research assistant, medical researcher, microbiologist, biochemist, or pharmacologist. (This is not to say that everyone in each of these professions participates in genetic engineering.) People whose occupations involve genetic engineering might work in a university, in private industry, or for the government. Speaking of the government, there are professionals in agencies such as the Environmental Protection Agency, the U.S. Department of Agriculture, the Food and Drug Administration, and the National Institutes of Health who may not perform genetic engineering themselves but are involved in either regulating genetically engineered products or recommending procedures for working with GEOs.

As scientists continue to research new uses and techniques for genetic engineering, their work is not without controversy (even within the scientific community). Some GE products have entered the marketplace without much to-do, while others have sparked debate and protest (more so in European nations than in the United States), not to mention new regulations, government guidelines, panels, and commissions.

Connections

To help your students learn about the science behind genetic engineering before they begin exploring careers, you might want to have them read and discuss this rundown of some of the areas of genetic engineering research and application:

• Transgenic crops: Scientists have engineered crops to be disease-resistant, insect-resistant, herbicide-tolerant, or salt-tolerant. They have also developed plants with enhanced nutritional content, modified oil content, or delayed ripening. And then there are the coffee plants (not on the market yet) engineered to produce up to 70 percent less caffeine without a correlated loss of taste. Sometimes two of these traits can be engineered into one crop plant, a so-called stacked variety. Researchers have also begun experimenting with the genetic engineering of plants to grow in previously inhospitable areas, including dry, salty, or cool habitats. Why is this biotech work done? Put simply, a typical goal is to enable farmers to produce more healthy crops with less labor. In addition, insect resistance can reduce farmers' use of pesticides, which may save them money and reduce their exposure to insecticides. We have used the word may because research on the true profitability and pesticide reduction brought about by GM crops is a relatively new and challenging area of research. Proponents of genetic engineering assert that GM crops have the potential to feed more people better food, to decrease the use of pesticides, and to promote the use of safer herbicides. Many scientists agree that we are only seeing the rudimentary beginnings of plant genetic engineering. So far, work has focused on getting a small number of traits into select species.³ The two most frequently engineered traits are herbicide tolerance and insect resistance (separately or together). As amazing as some of these acts of genetic engineering sound, they do not come without risks. Because of government regulatory guidelines and public perception, those who engineer GM crops must often address the environmental or human health risks that the plants may pose.



• Production of proteins for medical use: Pharming (or biopharming) is a term that describes the use of recombinant DNA technologies to engineer animals or plants to produce human or other animal proteins. Some sources limit the term to just animals or just plants, and some include the classic genetic engineering of bacteria, yeast, or animal cell lines. In general, the premise is the same across kingdoms--alter the genetic makeup of a target organism so it makes a desired protein. Since the 1980s, industry has synthesized certain human proteins this way, usually through the genetic engineering of bacteria or yeast. Examples include insulin, growth hormone, and tissue plasminogen activator (t-PA, a clot-dissolving protein). There are limitations to what can be synthesized and purified from these more traditional (if you can say that about genetic engineering) techniques, so researchers are also engineering farm animals and crops to produce pharmaceutical proteins like antibodies, enzymes, and hormones. These target proteins can be collected from the milk of GM animals, and, in an oft-cited example, it's possible that down the road people could get vaccinated by eating a GM fruit or vegetable. This delivery mode could mean vaccination programs would require fewer medical personnel or equipment, a real plus in developing nations. Much of this work is in the experimental or clinical trials stage. Proponents of pharming in crops and animals say it can allow companies to produce more product faster to keep up with the increasing demand for medicine. But concerns and critics abound. Some are ethically opposed to turning animals into factories, especially when many of the experiments fail and cause death or disease in the animals. Others fear that the transgene will spread to nonengineered organisms or harm wildlife that come in contact with it. A huge concern is that pharm (or pharma) crops will get into the animal feed or human food supply either through the escape of the transgene (cross-pollination between a pharm and a non-GM plant) or by accidental contamination of fields or food stores. This concern became less of a supposition in 2002 when a biotech company was fined for contaminating soybeans with the GM corn that it was field testing. The corn was designed to produce a vaccine for pigs. Although none of the soy reached the market, this incident and others put a media spotlight on pharming and the risks it entails. In an earlier non-pharming incident, StarLink, an insect-resistant GM corn approved only for animal feed, was detected in a variety of human food products. Government agencies have since toughened restrictions on these GM plants with the goal of keeping them out of the food supply.



• Gene therapy: Researchers are experimenting with a new way of treating disorders caused by a gene defect. Standard medical care often treats the symptoms instead of the causes of disease. In contrast, the intent of gene therapy is to remedy the problem at the level of the gene. There are different techniques, but overall the goal is to manipulate a person's DNA so that she'll no longer suffer from a particular disorder or disease. Usually researchers transfer an effective gene into a patient to replace a defective one. Viruses are the vectors often used to deliver the beneficial gene. As an example, gene therapy could alter a hemophiliac's genetic code so that instead of having to receive injections of a clotting factor, the patient could manufacture an adequate amount of the enzyme on her own. Currently this work is experimental, meaning laboratory studies and clinical trials (including some on hemophilia and cystic fibrosis) are being conducted, but gene therapies haven't been released for treating the public at large. The field has encountered many problems and disappointing results, most notably the 1999 death of 18-year-old Jesse Gelsinger. As part of a clinical trial, the young man received gene therapy for a deficient liver enzyme. His death was linked to the gene therapy. More recently, two children in France developed a leukemia-like disease in 2002 after receiving gene therapy. The therapy was heralded as the first success story of gene therapy (the children's X-linked severe combined immunodeficiency, or X-SCID, was alleviated), and then this sad development occurred. The health benefits of successful gene therapy are obvious, but the techniques have limitations and risks and have raised many ethical concerns. As Katherine High, a prominent gene therapy researcher, has said, "At this point, the field is not something to go into if you want to labor in obscurity. It's a highly visible field because of public, commercial, and political interest. That creates a great deal of pressure."⁴



• Transgenic animals: There's the pharming flavor of animal genetic engineering, and then there are other applications. GM animals such as mice and fruitflies are used extensively in laboratory research, often as models for studying human disease. Scientists also experiment with GM lab animals to investigate how genes are regulated (how their activity is governed). And in the fishy stream of things, a U.S. company has successfully engineered salmon to have an accelerated growth rate. At the time of printing, these GM salmon (which are intended for human consumption) had not yet been released to the market; they were still under review by the FDA. Other researchers and companies around the globe are also experimenting with the production of GM fish, such as carp and tilapia, that grow faster or larger or resist disease. These traits are a real boon to fish farmers. Some scientists, though, are concerned that transgenic fish could escape confinement and disrupt natural aquatic ecosystems. The GM fish might compete with their wild counterparts or mate with wild fish, spreading the transgene. Producers of these fish say they can build in safeguards such as rendering the GM fish sterile. The confinement of GMOs has become a hot topic in the scientific and regulatory communities. On a final fish-related note, the first transgenic pet appeared in pet stores around the nation (except in California, where it is banned) on January 5, 2004. The GloFish is a fluorescent zebrafish that glows red under certain wavelengths of light. It contains a gene from coral that codes for red fluorescent protein.



• Other applications: Academic, government, and industry researchers are also exploring other uses for genetic engineering technology. These include engineering microbes to clean up waste (bioremediation, an area of strict governmental oversight) or to indicate where certain types of pollution are present. Another avenue of application is the creation of GM microbes to produce enzymes for industrial use.

A study of genetic engineers and their work provides an excellent opportunity for students to explore how science and society intersect. Students may not have thought too much about the gatekeeping role that government agencies can play in determining which GM products can be field-tested and, from that group, which can be sold to the public. Some of the web resources below touch on this subject. Who knows--along the way, this may interest some students in a career in regulatory affairs.

The activities and videos listed below will give students a glimpse into the work of genetic engineers. You can also purchase kits from biological supply companies that allow for more hands-on experience with genetic engineering techniques. If possible, invite a professional in the field to dialogue with your class about her work or set up a field trip to visit a laboratory where genetic engineering is done.

Sources:
¹"Glossary of Biotechnology and Genetic Engineering," Food and Agriculture Organization of the United Nations, http://www.fao.org/DOCREP/003/X3910E/X3910E00.HTM, accessed 1/25/04.
²"Dictionary of Genetic Terms," in Genomics and Its Impact on Science and Society: A 2003 Primer, Human Genome Program, U.S. Department of Energy, http://www.ornl.gov/sci/techresources/Human_Genome/publicat/primer2001/glossary.shtml, accessed 1/26/04.
³Jikun Huang, Carl Pray, and Scott Rozelle, "Enhancing the Crops to Feed the Poor," Nature, August 8, 2002, vol. 418, pp. 678-684.
⁴Trisha Gura, "After a Setback, Gene Therapy Progresses ... Gingerly," Science, March 2, 2001, Vol. 291, pp. .

Web Resources

1. Genetic Science Learning Center
   
   http://gslc.genetics.utah.edu/
   (An ENC Digital Dozen selection, ENC#016488) Teachers, students, and parents will want to mine this rich site it for all it's worth! Whether you need a refresher on the basics of DNA or want to try gel electrophoresis virtually or in the classroom, you'll find what you need here. There are excellent sections of the site devoted, respectively, to genetic disorders, gene therapy, cloning, and stem cells. These sections, like the rest of the site, are replete with animations, images, and many interactive features. Teachers, don't miss the Teacher Resources section--that's where you'll find instructions for loads of classroom activities, including some on gene therapy and others on DNA extraction.
   
   
2. Gene Stories--Genes & Health: The Future
   
   http://www.bbc.co.uk/health/genes/future/intro.shtml
   This excellent resource on human genetics would work well for teachers and high school biology students alike (nothing too technical here). The author, a physician, talks about how the burgeoning body of human genetics knowledge and the applications of genetic engineering have begun to make a difference in how doctors treat patients. This resource does a super job describing future prospects for the use of genetic data and gene technologies. For example, based on genetic data, doctors could categorize diseases into smaller subgroups and then customize patients' treatments (whether with gene therapy or drugs) according to the specific type of disease that they have. Of course, applications of genetic data or technologies are not without controversy or ethical implications, which is why there is a segment here called Ethics and Law.
   
   
3. History of Plant Breeding
   
   http://www.colostate.edu/programs/lifesciences/TransgenicCrops/history.html
   Here's a nice overview of how humans have altered plants through the ages. Different plant breeding techniques are highlighted including cross-pollination, mutation breeding, tissue culture, and haploid breeding. The overview ends with a synopsis of the first plant genetic engineering experiments. Proponents and opponents of GM crops often argue whether genetic engineering is really different from other human modification of plants. Before weighing in on this debate, students could review this sheet to learn about these non-genetic engineering techniques. There are helpful links to illustrations and to further descriptions of many of the procedures.
   
   
4. Bio-Pharming
   
   http://www.colostate.edu/programs/lifesciences/TransgenicCrops/hotbiopharm.html
   This link--from the same site as the resource above--provides an excellent look at plant pharming. It talks about the risks and benefits of plant-made pharmaceuticals as well as who is doing this work and when the products are likely to reach the market. It also does a nice job summarizing how the government regulates these GM crops. There are lots of links to further references, and the closing paragraph poses important unanswered questions about pharm crops. (The rest of this transgenic crop site is also worth a look!)
   
   
5. Gene Therapy
   
   http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml
   An excellent source for teachers and high school students with a strong genetics background. Set up in question and answer format, this overview hits on lots of topics ranging from how gene therapy is done to the ethical concerns about it. Especially informative sections address the present status of gene therapy (including problems with experimental trials) and discuss reasons why gene therapy has not yet become a viable commercial means of treating patients. There are also plenty of links to additional high-quality references.
   
   
6. What is Biotechnology?
   
   http://www.upenn.edu/biotech/whatis.shtml
   Send students with a good background in biology to this link and they'll read brief highlights of the work that scientists are doing in different areas of biotechnology. The folks at the University of Pennsylvania's Masters in Biotechnology program give an overview of biotechnology and then break down key advances into categories like recombinant DNA and medical therapy. The advances aren't limited to applications of genetic engineering.
   
   
7. USDA Living Science: Biological Engineer
   
   http://www.agriculture.purdue.edu/USDA/careers/biosystemsengineer.html
   This link presents concise information on biological engineering, an emerging career field. Genetic engineering techniques are just some of the techniques used by biological engineers. The link gives a general definition of the discipline and lists the kinds of businesses that employ these engineers and the spectrum of work that they perform. There's also a nice summary of the knowledge, schooling, and skills that students will need to enter this discipline.
   
   
8. AgBiotech Buzz
   
   http://pewagbiotech.org/buzz/archive.php3
   This publication of The Pew Initiative on Food and Biotechnology is just marvelous. Access current and past issues on a range of topics related to agricultural biotechnology and GM foods. Topics have ranged from GM insects to federal regulation of pharmaceutical plants. This is an excellent source of interesting, timely readings for you and your students. Check out the Roundtable feature for opposing views on each issue's topic. And on a career note, the Profiles feature shines light on an organization or individual's experience with biotechnology work.
   
   

Ready-to-Go Activities

1. Recombinant DNA: Example Using Insulin
   
   http://www3.iptv.org/exploremore/ge/what/insulin.cfm
   Grades 8-12. Students can go here to see (literally) how bacteria or yeast can be genetically engineered to manufacture human insulin for diabetics who require this critical protein. Each step of the process is explained and illustrated. Plus, there's an extra feature to help students, especially visual learners, understand the process. When they rest their pointer over an image for a particular step, it becomes animated.
   
   
2. Iowa Public Television: Plant Biotechnology Manager #1131
   
   http://www.careers.iptv.org/people_detail.cfm?pplID=312&occID=151
   Grades 8-12. What an excellent video! You'll need the RealPlayer plug-in for students to view the full video, which lasts just over 5 minutes. Follow the link in the left margin to open it. The camera follows around a plant scientist at a biotech firm as she explains how she transforms (genetically engineers) a corn plant and talks about her career. Students get a view into some of the techniques and equipment used in genetic engineering (including the particle gun). Plus they can see the physical spaces (greenhouse, laboratory, and even a dark room) in which biotechnologists may work. The section that shows how transgenic embryos develop into young plants in Petri dishes is especially cool. If you can't play the video, a transcript and photos are available at http://www.careers.iptv.org/enhanced/1131/ec_dayinthelife_trans.cfm.
   
   
3. The Biotechniques Laboratory: Gel Electrophoresis
   
   http://gslc.genetics.utah.edu/units/biotech/gel/
   (Part of an ENC Digital Dozen selection, ENC#016488) Grades 9-12. This activity is part of the Genetic Science Learning Center resource cited in the Web Resources section above. This Flash-animated virtual lab lets students try their hand at gel electrophoresis, a lab technique frequently used by molecular biologists and genetic engineers to separate out DNA strands or proteins of different sizes. You'll want to give it a try, too--and turn on your speakers or headphones! What's especially nice about this activity is that students are given an introduction to gel electrophoresis before they participate in the mock gel run. Then they move into the lab where they interact with the necessary equipment and materials (agarose, gel holder and comb, DNA sample, microwave, micropipettor, etc.) to run their own gel and interpret the results. This could make a great pre-lab assignment before doing gel electrophoresis in class. The developers have even noted some of the safety precautions students would need to take if running a real gel.
   
   
4. Pharming for Farmaceuticals
   
   http://gslc.genetics.utah.edu/features/pharming/
   (Part of an ENC Digital Dozen selection, ENC#016488) Grades 9-12. This also is part of the Genetic Science Learning Center resource cited in the Web Resources section. We put this article in the activities section because two good animations supplement the text. The animations, one about the making of transgenic animals and the other about using retroviruses to pass along the transgene, help bring to life what students will read about pharming. Here the focus is on engineering animals to manufacture medically important proteins. Sections cover the techniques, the experimental efforts, and the pros and cons of this controversial work.
   
   
5. The New, Improved Garden?
   
   http://gslc.genetics.utah.edu/features/gmfoods/
   (Part of an ENC Digital Dozen selection, ENC#016488). Grades 9-12. Like the previous two links, this one also is taken from the Genetic Science Learning Center site listed in the Web Resources section. This feature sets up three hypothetical situations in which plant genetic engineering could possibly save the day. Groups of students can discuss what they would do in each of the three scenarios and then review the rest of the feature. It gives a nice brief summary of genetic engineering with an excellent sidebar illustration of how a transgenic tomato plant is produced using a gene gun. (This tomato is not yet sold.) Two of the main concerns about GM plants are discussed, and students are encouraged to learn more about GMOs as part of their civic duty.
   
   
6. Engineer a Crop
   
   http://www.pbs.org/wgbh/harvest/engineer/
   Grades 9-12. Students get behind the wheel of traditional plant breeding and genetic engineering to see what these techniques entail. Shockwave and Flash plug-ins are needed for the two interactive simulations. As selective breeders, each year students choose an ear of corn to keep as seed for the next season's crop. Then, in the transgenic activity, they use their mouse to create a plant with the Bt gene, a bacterial gene that codes for an insecticide. After each step is completed, the science behind it is explained.
   
   
7. DNA--Episode 2: Playing God
   
   http://www.pbs.org/wnet/dna/episode2/index.html#
   Grades 9-12. The center part of this PBS page has nice information on the early history of genetic engineering, but we really picked this link for its three sidebars. The first, the Gallery of Genetic Modifications, provides vignettes on four types of GM foods including Bt corn and golden rice. Each vignette touches on the science behind the GM crop and the conceivable advantages and disadvantages to producing it. The second sidebar is a link to a magnificent video clip about the creation of a bacterium with a toad gene in it. It's definitely worth sharing this video with your students. It runs just over 3 minutes and highlights how two scientists, Herbert Boyer and Stanley Cohen, collaborated to become the first to genetically engineer an organism with DNA from a different species. Finally, the third sidebar is an illustrated explanation of gene therapy, showing how a virus can be used to deliver a beneficial gene to human cells.
   
   
8. DNAi: Manipulation
   
   http://www.dnai.org/b/index.html
   (Part of an ENC Digital Dozen selection, ENC#028549) Grades 9-12. A truly fantastic and fascinating set of modules! The first, Revolution, does a remarkable job presenting both the landmark discoveries that led to the creation of recombinant DNA and the emerging controversy surrounding this work. Scientists had to figure out how to cut, paste, and copy DNA (sounds like word processing commands, right?), and here we get to hear many of those scientists talk about their own work and see animations of the procedures. The second module, Techniques, combines text, animations, and interviews to explain those and other key processes in the manipulation of DNA. For example, students can hear a scientist explain how agrobacteria and gene guns are used to deliver transgenes. Production, the third module, tells how two biotech companies fought to be the first to make synthetic human insulin.
   
   

Classroom Resources from the ENC Collection

1. Genetic engineering, how DNA works
   Date: 2001 Grade(s): 9 - 12 Cost: $129.95 ENC#: 028273
   This video is the first in an excellent series titled Genetic Engineering: Dreams and Nightmares. We recommend all three videos in the series. The sequencing of content, video length (the longest video is only 21 minutes), and engaging visual mix of diagrams, images, and laboratory footage are all pluses of this series. As the title indicates, the first video deals with the basics of DNA. Professor David Cove (University of Leeds) does a super job of building students' understanding of basic DNA structure and function. DNA replication, the coding of the amino acids that make up proteins, and the significance of promoters are all addressed without bogging students down in irrelevant detail or terminology. In the second video (ENC#028055), students are introduced to the four fundamental steps in genetic engineering: the "isolation, cloning, delivery, and control" of the gene in question. Students get to observe two especially interesting genetic engineering techniques: the shooting of DNA into a sample of moss to alter the moss's genome and the use of green fluorescent protein (GFP), a product of a jellyfish gene, to determine where and if a transferred gene is working. Once students have a basic understanding of the science behind genetic engineering, they are ready to view the third tape, (ENC#028285), where they are introduced to current and potential products and uses of genetic engineering and different views on the risks and benefits of it. Although Dr. Cove stresses that students will have to make up their own minds regarding genetic engineering, he shares that his largest concern lies in the area of human genetics. He discusses the potential for discrimination if we screen humans for genetic predispositions toward diseases or disorders that we cannot yet treat.
   (For more details see ENC Record)
   
   
   
2. Genetic engineering: opposing viewpoints
   Date: 2001 Grade(s): 6 - 12 Cost: $22.45 ENC#: 028164
   Want to expose your students to different opinions and challenge them to think critically about genetic engineering and its ramifications for society? The editors of this volume have set you (and your students) up for success. They've compiled and edited original works from a variety of individuals--scientists, journalists, professors in economics, theology, and law, and others. For every "pro" view, there is one against the same issue. Students are given questions to contemplate as they read each entry, plus there are discussion questions at the end of the book. The impact of genetic engineering on society, its regulation, GE food, and the engineering of humans are addressed.
   (For more details see ENC Record)
   
   
   

Search Strategies

Find more materials by searching Curriculum Resources on ENC Online using these terms: Biotechnology, DNA, Genes, Genetic code, Genetic disorders, Genetic engineering, Geneticist, Genetics, or Recombinant DNA.

Connections to Standards

Realizing that there are many ways to use this Classroom Calendar entry, we chose these standards because they relate to the entry, in full or in part. If you want to explore the standards further, please use the link(s) provided.

Connections to NSES
Content Standard C: Life Science: Molecular basis of heredity (9-12)
Content Standard E: Science and Technology: Understanding about science and technology (9-12)
Content Standard F: Science in Personal and Social Perspectives: Science and technology in local, national, and global challenges (9-12)
Content Standard G: History and Nature of Science: Science as a human endeavor (9-12)