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- Introduction to Genetic Engineering and Its Applications
Lesson Introduction to Genetic Engineering and Its Applications
Grade Level: 9 (9-12)
(Consider adding 30 minutes for a thorough ethics discussion.)
Lesson Dependency: None
Subject Areas: Biology
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Genetic engineers have developed genetic recombination techniques to manipulate gene sequences in plants, animals and other organisms to express specific traits. Applications for genetic engineering are increasing as engineers and scientists work together to identify the locations and functions of specific genes in the DNA sequence of various organisms. Once each gene is classified, engineers develop ways to alter them to create organisms that provide benefits such as cows that produce larger volumes of meat, fuel- and plastics-generating bacteria, and pest-resistant crops.
After this lesson, students should be able to:
- List several present day applications of genetic engineering.
- Describe general techniques used by genetic engineers to modify DNA.
- Analyze the benefits and drawbacks of manipulating an organism's DNA.
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A basic understanding of protein synthesis and DNA's role in the cell/body is helpful so students can follow how changes in DNA result in major changes in the characteristics of organisms.
(Make copies of the Genetic Engineering Flow Chart , one per student. Hand out the blank flow charts for students to fill in during the presentation and lecture. Then show the class the 16-slide Genetic Engineering Presentation , a PowerPoint® file. Open with two images of the same organism: one that has been genetically engineered and one that has not. Examples: two ears of corn in which the non-modified one is diseased; two cows in which the modified one is larger; or, since students really respond to bioluminescent organisms, show two mice in which one has been modified to glow green. Slide 2 shows two examples of modified versus non-modified mice. Another idea is to show two organisms that look the same even though one has been modified as an example of how most modifications are not visible.)
What is the difference between these two organisms? (Answers will vary, depending on the image shown.) Even though they are the same organism, why are they are different? (Answer: Genetic engineering. Some students may not come to this answer on their own. Expect some to suggest mutations.) The difference is due to genetic engineering. The animal (or plant) that has been changed is called a genetically modified organism, or GMO.
How do engineers change the traits of organisms? (Listen to student ideas.) DNA contains all of the genetic information to determine an organism's traits or characteristics. By modifying the DNA, engineers are able to determine which traits an organism will possess.
(Continue through the presentation: What is genetic engineering? History of GMO Development, What is the GMO process? Then starting with slide 6 , go through the provided examples of GMO bacteria, plants and animals. Emphasize the reasons for modifying each organism [ slide 10 ].)
(Show the slide 14 picture of a man and spider.) Can anyone guess what would happen if we combined the DNA from these two creatures? (Expect students to enthusiastically answer "spiderman.") Could engineers create a "spiderman" in the lab today? (Expect some yes responses, while most students answer no.) Not quite. However, in 2000, engineers created the first goat able to produce spider silk proteins (an amazingly strong and elastic fiber with futuristic benefits in construction [bridge suspension cables, airbags that are gentler for passengers], medicine [artificial skin to heal burns, artificial ligaments, thread for stitching wounds] and the military [body armor] if sufficient quantities could be generated), so maybe it is not too far away.
(Show slide 15 .) Genetic engineering is so new and astonishing that people are still trying to figure out the pros and cons. We saw some examples of the benefits from genetically modified organisms, what about the disadvantages and harm caused by genetic engineering? (After listening to student ideas, go through the concerns listed on the slide. Alternatively, go through the contents of this slide and background information as a class discussion during the Lesson Closure, extending the lesson time as necessary.)
(Continue on to present students with the content in the Lesson Background section, and then a class review of the completed flow charts.)
Lesson Background and Concepts for Teachers
What is DNA?
Deoxyribonucleic acid (DNA) is a large biomolecule that contains the complete genetic information for an organism. Every cell of living organisms and many viruses, contains DNA. The basic building block of a DNA molecule is called a nucleotide , and a single strand of DNA may contain billions of nucleotides. (Refer to Figure 1 to see the DNA structure with labeled parts.) Although each DNA molecule contains many of these building blocks, only four unique nucleotides are used to create the entire DNA sequence; these are written as A, G, C and T. Analogous to how the 26 letters of the alphabet can be arranged to create words with different meanings, these four nucleotides can be arranged in sequences to "spell" the genetic instructions to create all of the different proteins organisms need to live.
Why are proteins important?
Proteins perform all of the work in organisms. Some functions of proteins include:
- Serving as catalysts for reactions
- Performing cell signaling
- Transporting molecules across membranes
- Creating structures
When a protein is created by its gene, it is said that the gene is "expressed," or used. Most gene expressions do not produce results visible to the unaided eye. However some genes, such as those that code for proteins responsible for pigment, do have visual expression. The expression of a gene in an observable manner is called a phenotypic trait ; one example is an organism's hair color. In fact, everything you can see in an organism is a result of proteins or protein actions.
How is DNA used in genetic engineering?
By definition, genetic engineering is the direct altering of an organism's genome. This is achieved through manipulation of the DNA. Doing this is possible because DNA is like a universal language; all DNA for all organisms is made up of the same nucleotide building blocks. Thus, it is possible for genes from one organism to be read by another organism. In the cookbook analogy, this equates to taking a recipe from one organism's cookbook and putting into another cookbook. Now imagine that all cookbooks are written in the same language; thus, any recipe can be inserted and used in any other cookbook.
In practice, since DNA contains the genes to build certain proteins, by changing the DNA sequence, engineers are able to provide a new gene for a cell/organism to create a different protein. The new instructions may supplement the old instructions such that an extra trait is exhibited, or they may completely replace the old instructions such that a trait is changed.
Genetic Engineering Technique
The process for genetic engineering begins the same for any organism being modified (see Figure 3 for an example of this procedure).
- Identify an organism that contains a desirable gene.
- Extract the entire DNA from the organism.
- Remove this gene from the rest of the DNA. One way to do this is by using a restriction enzyme . These enzymes search for specific nucleotide sequences where they will "cut" the DNA by breaking the bonds at this location.
- Insert the new gene to an existing organism's DNA. This may be achieved through a number of different processes.
Once the recombinant DNA has been built, it can be passed to the organism to be modified. If modifying bacteria, this process is quite simple. The plasmid can be easily inserted into the bacteria where the bacteria treat it as their own DNA. For plant modification, certain bacteria such as Agrobacterium tumefaciens may be used because these bacteria permit their plasmids to be passed to the plant's DNA.
Applications and Economics
The number of applications for genetic engineering are increasing as more and more is learned about the genomes of different organisms. A few interesting or notable application areas are described below.
How many of today's crops are genetically modified? As of 2010, in the U.S., 86% of corn produced was genetically modified. Bt -corn is a common GMO that combines a gene from the Bt bacteria with corn DNA to produce a crop that is insect-resistant. The bacteria gene used contains a recipe for a protein that is toxic when consumed by insects, but safe when consumed by humans.
A number of other genes can be combined with crops to produce desirable properties such as:
- Herbicide-, drought-, freeze- or disease-resistance
- Higher yield
- Faster growth
- Improved nutrition
- Longer shelf life
The creation of genetically modified crops provides many incentives for farmers and businesses. When farmers are able to plant a crop that has a higher yield per acre, they can significantly increase production, and thus sales, with minimal cost. Disease, pest and other resistances reduce crop loss, which also helps to increase profits. Besides farmers, other benefactors from modified crops include seed, agrochemical and agriculture equipment companies as well as distributors and universities that are involved in GMO research. In 2011, the value of genetically modified seed was $13.2 billion in the U.S. alone. The value of the end products produced from these seeds topped $160 billion.
Due to their simple structures, the most commonly modified organisms are bacteria. The first modified bacteria were created in 1973. Bacteria can be modified to produce desirable proteins that can be harvested and used. One example is insulin or spider silk, which is difficult to gather naturally. Other modifications to bacteria include making changes to the cellular respiration process to alter the byproducts; typically CO 2 is produced, however engineers have made modifications so that hydrocarbon byproducts such as diesel and polyethylene (a fuel and a plastic) are produced.
(The 30-minute lesson time leaves a fair amount of time for discussion, but since class participation will vary, you may want to extend the lesson another 30-minutes to allow for a thorough discussion of the ethical implications of genetic engineering. This makes a good student research and debate topic, too.)
The main reason genetically modified organisms are not more widely used is due to ethical concerns. Nearly 50 countries around the world, including Australia, Japan and all of the countries in the European Union, have enacted significant restrictions or full bans on the production and sale of genetically modified organism food products, and 64 countries have GMO labeling requirements. Some issues to consider when deciding whether to create and/or use GMOs include:
Safety: This generally arises in the case of GMO foods. Are the foods safe for human consumption? Is GMO feed healthy for animals? Many opponents of GMO foods say not enough independent testing is done before the food is approved for sale to consumers. In general, research has shown that GMO foods are safe for humans. Another safety consideration is the health of farmers and their families, animals and communities who are put at risk with exposure to chemicals used in tandem with GMO seeds.
Environmental Impact: Consider that genetic engineers have the ability to create trees that grow faster than their unmodified counterparts. This seems like a great deal for the lumber industry, but might some unintended consequences result? Being outdoors and grown in large quantities, the modified trees may cross-pollinate with unmodified trees to form hybrids outside of designated growing areas. This in return could create trees that could disrupt the ecosystem. For example, they could overpopulate the area or grow so large that they smother other plant life. This same scenario has unintended and undesirable consequences when the pollen from GMO crops drifts into non-GMO fields.
Humans: Should humans be genetically engineered? Doing so could have medical applications that reduce or prevent genetic disorders such as Down's syndrome. However, the bigger question is where should engineering humans stop? Should parents be allowed to decide their children's eye colors, heights or even genders before birth?
Watch this activity on YouTube
What part of an organism contains all of the information needed for it to function? (Answer: DNA) When genes are expressed, what is the final product made? (Answer: Proteins) Does anyone know why bacteria are modified more than other organisms? (Answer: With their very simple structures and ability to use plasmids, bacteria are much easier and less costly to modify.)
What are some ethical and moral concerns that genetic engineers must consider? Does anyone think it is a good idea to genetically modify people? Some researchers say this could be an approach to cure diseases such as Down's syndrome and other genetic defects. Superficial changes could also be made, such as determining a person's height, eye color or gender, by making changes to embryos in the mothers' wombs. But just because something can be done, does that make it a good idea? (Answer: No. This is a good topic for an extended discussion.)
DNA: Acronym for deoxyribonucleic acid, which is a molecule that contains an organism's complete genetic information.
gene: The molecular unit of an organism that contains information for a specific trait (specific DNA sequence).
genome: An entire set of genes for an organism.
GMO: Acronym for genetically modified organism.
nucleotide: The building block of DNA.
plasmid: The circular DNA structure used by bacteria.
protein: Large biomolecules used by an organism for a number of purposes; in this context, to express a desired trait.
recombinant DNA: DNA to which a section has been removed and replaced (recombined) with a new sequence.
restriction enzyme: An enzyme that "cuts" DNA when specific base pair sequences are present.
trait: A distinguishing characteristic.
Discussion Questions: Initiate a brief discussion to gauge whether students have heard of or know anything about genetics. Ask questions such as:
- Why are your eyes the color that they are?
- Would anyone like to be taller (or shorter)?
- Is there any way to make these changes?
Flow Chart: Have students complete the Genetic Engineering Flow Chart during the course of the lesson. After delivering the presentation and lecture, go through the flow chart as a class, so that students can complete anything they missed and check their flow charts for accuracy. Answers are provided on the Genetic Engineering Flow Chart Answer Key .
Lesson Summary Assessment
Recombinant Creature Design : Have students in pairs (or individually) create their own recombinant organisms. Direct students to pick any organism and decide what gene they would like to add. If desired, provide a list of genes from which they can choose (such as genes that makes an organism smarter, bigger, faster, grow extra limbs, etc.). To encourage critical thinking, require students to write down a potential use for the resulting creatures. Finally, have students sketch what their recombinant creatures would look like.
View some genetic engineering examples (with photographs) at: http://www.mnn.com/green-tech/research-innovations/photos/12-bizarre-examples-of-genetic-engineering/
Show students some applications of spider silk at Popular Mechanics' "6 Spider-Silk Superpowers" slide show at http://www.popularmechanics.com/science/health/med-tech/6-spider-silk-superpowers#slide-1
As a class, students work through an example showing how DNA provides the "recipe" for making human body proteins. They see how the pattern of nucleotide bases (adenine, thymine, guanine, cytosine) forms the double helix ladder shape of DNA, and serves as the code for the steps required to make gene...
Students learn about mutations to both DNA and chromosomes, and uncontrolled changes to the genetic code. They are introduced to small-scale mutations (substitutions, deletions and insertions) and large-scale mutations (deletion duplications, inversions, insertions, translocations and nondisjunction...
Students reinforce their knowledge that DNA is the genetic material for all living things by modeling it using toothpicks and gumdrops that represent the four biochemicals (adenine, thiamine, guanine, and cytosine) that pair with each other in a specific pattern, making a double helix. Student teams...
Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms.
12 Bizarre Examples of Genetic Engineering. Posted October 27, 2010. MNN Holdings, Mother Nature Network. Accessed December 8, 2013. http://www.mnn.com/green-tech/research-innovations/photos/12-bizarre-examples-of-genetic-engineering
Biello, David. Turning Bacteria into Plastic Factories. Posted September 16, 2008. Scientific American. Accessed December 11, 2013. http://www.scientificamerican.com/article.cfm?id=turning-bacteria-into-plastic-factories-replacing-fossil-fuels
DNA. Updated June 7, 2014. Wikipedia, The Free Encyclopedia. Accessed June 16, 2014. http://en.wikipedia.org/wiki/DNA
Emspak, Jesse. Gut Bacteria Make Diesel Fuel. Posted April 23, 2013. Discovery Communications. Accessed December 11, 2013. http://news.discovery.com/tech/biotechnology/gut-bacteria-make-diesel-fuel-130423.htm
Genetic engineering. Updated December 7, 2013. Wikipedia, The Free Encyclopedia. Accessed December 9, 2013. http://en.wikipedia.org/wiki/Genetic_engineering
Genetically modified crops. Updated June 12, 2014. Wikipedia, The Free Encyclopedia. Accessed June 16, 2014. http://en.wikipedia.org/wiki/Genetically_modified_crops
Straley, Regan. GMO Food Concerns. Posted August 29, 2014. Lancaster Online, Lancaster, PA. Accessed August 31, 2014. http://lancasteronline.com/opinion/gmo-food-concerns/article_3c5092ba-2ed0-11e4-ab00-001a4bcf6878.html
Vierra, Craig, et al. The Future of Biomaterial Manufacturing: Spider Silk Production from Bacteria. Posted July 17, 2012. Journal of Visualized Experiments (JoVE). Accessed December 11, 2013. http://www.jove.com/about/press-releases/39/the-future-biomaterial-manufacturing-spider-silk-production-from
What is genetic engineering and how does it work? Updated 2005. University of Nebraska. Accessed December 10, 2013. http://agbiosafety.unl.edu/basic_genetics.shtml
Other Related Information
(optional: Show students the What Is Engineering? video)
Supporting program, acknowledgements.
This digital library content was developed by the University of Houston's College of Engineering under National Science Foundation GK-12 grant number DGE 0840889. However, these contents do not necessarily represent the policies of the NSF and you should not assume endorsement by the federal government.
Last modified: May 12, 2021
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60 Interesting Genetic Engineering Topics for Your Next Research Paper
Genetics engineering is one of the popular areas of study today. The discipline was discovered back in 1850 and seeks to analyze the systems of heredity and genes in different species. Therefore, when your professor gives you assignments prompts, it is important to start by picking the right genetics topics for research papers.
However, many students find selecting the best genetics project ideas difficult. So, if you find yourself staring at a blank page for hours, you are not alone. But we are here to help!
To get you started on the right path, we have listed 60 hot genetic engineering topics for your research paper. Furthermore, we have provided you with pro tips for crafting A-rated research papers.
The Best Molecular Genetics Topic Ideas
- Stem cells: What are their potential and shortcomings?
- A closer look at the genome evolution.
- The molecular techniques of analyzing DNA and RNA.
- Evaluating the power of mutagenesis.
- DNA as an agent of heredity: A comprehensive analysis.
- Bacteria and genetics.
- Genetics: How does it increase the risk of cancer?
- Contemporary issues in genetic engineering public policy.
- Molecular cancer genetics: What are the latest advances?
Interesting Genetics Topics
- What are the main applications of genetics today?
- Discuss the main causes of genetic mutations.
- What is the link between genetics and obesity?
- RNA information.
- Do we have living cells in genes? Explain.
- Explain the role of genetics in the fight against Alhzeimer’s disease.
- An evaluation of genes replacement with artificial chromosomes.
- Genetics and depression: Are they linked?
- What are the impacts of genetics on future generations?
- What is the link between Parkinson’s disease and genetics?
- Can DNA changes help to beat aging?
- Discuss the morality of growing human organs.
- Genetics and homosexuality: Are they linked?
- A closer look at the history of human cloning.
- How do addictive substances impact our genes?
Top Genetics Topics for Presentation
- Should genetic engineering be legalized?
- What are the principles of genetic engineering?
- Analyzing the impact of cloning on modern medicine.
- A review of the latest studies on genetically modified organisms.
- Do we really need genetics testing?
- Artificial inseminations vs normal conception: What are your thoughts?
- Should parents be allowed to order genetically perfect children?
- A close look at the accuracy in genetic engineering.
- Should biotech firms be allowed to patent human genes?
- What are the pros and cons of genetic engineering?
- How does genetic engineering impact our relationships?
- Genetic engineering and the sale of human organisms.
- Ethics of genetic engineering: Should we support cloning of dead people?
- How is genetic engineering presented in the media today?
- Should researchers be obliged to share the benefits and burden of their work on genetic engineering?
Hot Topics on Genetics Engineering
- Are genetically modified foods safe for human consumption?
- Analyzing the philosophical issues of genetic engineering.
- Should the US government invest in genetic engineering?
- Impact of social media on genetically modified organisms discussions.
- Should using genetically modified foods to fight hunger be allowed?
- Comparing the genetic engineering policies of the US and UK.
- Cloning pets: Is it ethically right?
- Does cloning increase or limit biological diversity?
- The comprehensive analysis of the 2001 George W. Bush speech on cloning.
- Discuss the five main ethical dilemmas of genetic cloning.
- Whole-genome sequencing.
- Evaluating the top three gene-editing technologies.
- How does human microbiome work in preventing diseases?
- Genomic hybridization for enhanced fruits production.
- A closer look at CCR5 Delta 32 Genetic Mutation.
- The pros and cons of studies on biological dark matter.
- Biotic mutation for enhanced bone density.
- Using genetic mutation to eliminate sickle cell anemia.
- How does IVF help to prevent babies from inheriting genetic defects?
- Using genetic engineering to address the problem of genetic engineering.
- What is the future of cloning?
Special Tips for Writing a Great Research Paper
Once you have selected the preferred genetics topic for research papers, your journey to creating an A-rated paper has just started. Here are some useful tips to help you craft the best research paper on genetic engineering.
- Research on your selected topic comprehensively. This will help you to develop the right research questions and identify key points to discuss on the paper. Make sure to also capture the counter-arguments on the selected topic.
- Develop a good paper structure. Once you have picked the best research ideas, you need to craft a good structure so that the paper looks coherent and enjoyable to read. The format will help you to know what point to discuss at any part of the paper.
- Make sure to read other genetic engineering research papers to understand how experts did it. Here, you can borrow the structure and enrich your arguments from the discussions by other scholars.
- Proofread your work well. Even if you have the best genetics research topics and a good paper, but fail to proofread it well, there is a danger of scoring poor grade. So, make sure to proofread your work well to identify and correct errors, incomplete sentences, and flow. You can ask a professional to proofread and edit your paper , to ensure that your work is mistake-free.
When you are faced with a genetic engineering assignment, it is important to look at it holistically. So, start by identifying the most interesting genetic topics and use a good structure to craft the best paper.
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Unit 6: Gene expression and regulation
About this unit, dna and rna structure.
- Introduction to nucleic acids and nucleotides (Opens a modal)
- DNA (Opens a modal)
- Molecular structure of DNA (Opens a modal)
- Molecular structure of RNA (Opens a modal)
- Nucleic acids (Opens a modal)
- Prokaryote structure (Opens a modal)
- DNA and RNA structure Get 3 of 4 questions to level up!
- Antiparallel structure of DNA strands (Opens a modal)
- Leading and lagging strands in DNA replication (Opens a modal)
- Speed and precision of DNA replication (Opens a modal)
- Semi conservative replication (Opens a modal)
- Molecular mechanism of DNA replication (Opens a modal)
- DNA structure and replication review (Opens a modal)
- Replication Get 3 of 4 questions to level up!
Transcription and RNA processing
- Transcription and mRNA processing (Opens a modal)
- Post-transcriptional regulation (Opens a modal)
- Eukaryotic gene transcription: Going from DNA to mRNA (Opens a modal)
- Overview of transcription (Opens a modal)
- Eukaryotic pre-mRNA processing (Opens a modal)
- Transcription and RNA processing Get 3 of 4 questions to level up!
- Translation (mRNA to protein) (Opens a modal)
- Overview of translation (Opens a modal)
- Retroviruses (Opens a modal)
- Differences in translation between prokaryotes and eukaryotes (Opens a modal)
- DNA replication and RNA transcription and translation (Opens a modal)
- Intro to gene expression (central dogma) (Opens a modal)
- The genetic code (Opens a modal)
- Translation Get 3 of 4 questions to level up!
Regulation of gene expression and cell specialization
- DNA and chromatin regulation (Opens a modal)
- Regulation of transcription (Opens a modal)
- Cellular specialization (differentiation) (Opens a modal)
- Non-coding RNA (ncRNA) (Opens a modal)
- Operons and gene regulation in bacteria (Opens a modal)
- Overview: Gene regulation in bacteria (Opens a modal)
- Lac operon (Opens a modal)
- The lac operon (Opens a modal)
- Trp operon (Opens a modal)
- The trp operon (Opens a modal)
- Overview: Eukaryotic gene regulation (Opens a modal)
- Transcription factors (Opens a modal)
- Regulation of gene expression and cell specialization Get 3 of 4 questions to level up!
- An introduction to genetic mutations (Opens a modal)
- Mutagens and carcinogens (Opens a modal)
- The effects of mutations (Opens a modal)
- Impact of mutations on translation into amino acids (Opens a modal)
- Mutation as a source of variation (Opens a modal)
- Aneuploidy & chromosomal rearrangements (Opens a modal)
- Genetic variation in prokaryotes (Opens a modal)
- Evolution of viruses (Opens a modal)
- Mutations Get 3 of 4 questions to level up!
- Introduction to genetic engineering (Opens a modal)
- Intro to biotechnology (Opens a modal)
- DNA cloning and recombinant DNA (Opens a modal)
- Overview: DNA cloning (Opens a modal)
- Polymerase chain reaction (PCR) (Opens a modal)
- Gel electrophoresis (Opens a modal)
- DNA sequencing (Opens a modal)
- Applications of DNA technologies (Opens a modal)
- Biotechnology Get 3 of 4 questions to level up!
Although classical methods of studying the function of genes began with a given phenotype and determined the genetic basis of that phenotype, modern techniques allow researchers to start at the DNA sequence level and ask: “What does this gene or DNA element do?” This technique, called reverse genetics, has resulted in reversing the classic genetic methodology. This method would be similar to damaging a body part to determine its function. An insect that loses a wing cannot fly, which means that the function of the wing is flight. The classical genetic method would compare insects that cannot fly with insects that can fly, and observe that the non-flying insects have lost wings. Similarly, mutating or deleting genes provides researchers with clues about gene function. The methods used to disable gene function are collectively called gene targeting. Gene targeting is the use of recombinant DNA vectors to alter the expression of a particular gene, either by introducing mutations in a gene, or by eliminating the expression of a certain gene by deleting a part or all of the gene sequence from the genome of an organism.
Genetic Diagnosis and Gene Therapy
The process of testing for suspected genetic defects before administering treatment is called genetic diagnosis by genetic testing. Depending on the inheritance patterns of a disease-causing gene, family members are advised to undergo genetic testing. For example, women diagnosed with breast cancer are usually advised to have a biopsy so that the medical team can determine the genetic basis of cancer development. Treatment plans are based on the findings of genetic tests that determine the type of cancer. If the cancer is caused by inherited gene mutations, other female relatives are also advised to undergo genetic testing and periodic screening for breast cancer. Genetic testing is also offered for fetuses (or embryos with in vitro fertilization) to determine the presence or absence of disease-causing genes in families with specific debilitating diseases.
Gene therapy is a genetic engineering technique used to cure disease. In its simplest form, it involves the introduction of a good gene at a random location in the genome to aid the cure of a disease that is caused by a mutated gene. The good gene is usually introduced into diseased cells as part of a vector transmitted by a virus that can infect the host cell and deliver the foreign DNA (Figure 1). More advanced forms of gene therapy try to correct the mutation at the original site in the genome, such as is the case with treatment of severe combined immunodeficiency (SCID).
Production of Vaccines, Antibiotics, and Hormones
Traditional vaccination strategies use weakened or inactive forms of microorganisms to mount the initial immune response. Modern techniques use the genes of microorganisms cloned into vectors to mass produce the desired antigen. The antigen is then introduced into the body to stimulate the primary immune response and trigger immune memory. Genes cloned from the influenza virus have been used to combat the constantly changing strains of this virus.
Antibiotics are a biotechnological product. They are naturally produced by microorganisms, such as fungi, to attain an advantage over bacterial populations. Antibiotics are produced on a large scale by cultivating and manipulating fungal cells.
Recombinant DNA technology was used to produce large-scale quantities of human insulin in E. coli as early as 1978. Previously, it was only possible to treat diabetes with pig insulin, which caused allergic reactions in humans because of differences in the gene product. Currently, the vast majority of diabetes suffers who inject insulin do so with insulin produced by bacteria.
Human growth hormone (HGH) is used to treat growth disorders in children. The HGH gene was cloned from a cDNA library and inserted into E. coli cells by cloning it into a bacterial vector. Bacterial HGH can be used in humans to reduce symptoms of various growth disorders.
Although several recombinant proteins used in medicine are successfully produced in bacteria, some proteins require a eukaryotic animal host for proper processing. For this reason, the desired genes are cloned and expressed in animals, such as sheep, goats, chickens, and mice. Animals that have been modified to express recombinant DNA are called transgenic animals. Several human proteins are expressed in the milk of transgenic sheep and goats, and some are expressed in the eggs of chickens. Mice have been used extensively for expressing and studying the effects of recombinant genes and mutations.
Manipulating the DNA of plants (i.e., creating GMOs) has helped to create desirable traits, such as disease resistance, herbicide and pesticide resistance, better nutritional value, and better shelf-life (Figure 3). Plants are the most important source of food for the human population. Farmers developed ways to select for plant varieties with desirable traits long before modern-day biotechnology practices were established.
Plants that have received recombinant DNA from other species are called transgenic plants. Because they are not natural, transgenic plants and other GMOs are closely monitored by government agencies to ensure that they are fit for human consumption and do not endanger other plant and animal life. Because foreign genes can spread to other species in the environment, extensive testing is required to ensure ecological stability. Staples like corn, potatoes, and tomatoes were the first crop plants to be genetically engineered.
Transformation of Plants Using Agrobacterium tumefaciens
Gene transfer occurs naturally between species in microbial populations. Many viruses that cause human diseases, such as cancer, act by incorporating their DNA into the human genome. In plants, tumors caused by the bacterium Agrobacterium tumefaciens occur by transfer of DNA from the bacterium to the plant. Although the tumors do not kill the plants, they make the plants stunted and more susceptible to harsh environmental conditions. Many plants, such as walnuts, grapes, nut trees, and beets, are affected by A. tumefaciens . The artificial introduction of DNA into plant cells is more challenging than in animal cells because of the thick plant cell wall.
Researchers used the natural transfer of DNA from Agrobacterium to a plant host to introduce DNA fragments of their choice into plant hosts. In nature, the disease-causing A. tumefaciens have a set of plasmids, called the Ti plasmids (tumor-inducing plasmids), that contain genes for the production of tumors in plants. DNA from the Ti plasmid integrates into the infected plant cell’s genome. Researchers manipulate the Ti plasmids to remove the tumor-causing genes and insert the desired DNA fragment for transfer into the plant genome. The Ti plasmids carry antibiotic resistance genes to aid selection and can be propagated in E. coli cells as well.
The Organic Insecticide Bacillus thuringiensis
Bacillus thuringiensis (Bt) is a bacterium that produces protein crystals during sporulation that are toxic to many insect species that affect plants. Bt toxin has to be ingested by insects for the toxin to be activated. Insects that have eaten Bt toxin stop feeding on the plants within a few hours. After the toxin is activated in the intestines of the insects, death occurs within a couple of days. Modern biotechnology has allowed plants to encode their own crystal Bt toxin that acts against insects. The crystal toxin genes have been cloned from Bt and introduced into plants. Bt toxin has been found to be safe for the environment, non-toxic to humans and other mammals, and is approved for use by organic farmers as a natural insecticide.
Flavr Savr Tomato
The first GM crop to be introduced into the market was the Flavr Savr Tomato produced in 1994. Antisense RNA technology was used to slow down the process of softening and rotting caused by fungal infections, which led to increased shelf life of the GM tomatoes. Additional genetic modification improved the flavor of this tomato. The Flavr Savr tomato did not successfully stay in the market because of problems maintaining and shipping the crop.
Unless otherwise noted, images on this page are licensed under CC-BY 4.0 by OpenStax.
OpenStax, Biology. OpenStax CNX. May 27, 2016 http://cnx.org/contents/[email protected]:8CA_YwJq@3/Cloning-and-Genetic-Engineerin
Moen I, Jevne C, Kalland K-H, Chekenya M, Akslen LA, Sleire L, Enger P, Reed RK, Oyan AM, Stuhr LEB. 2012. Gene expression in tumor cells and stroma in dsRed 4T1 tumors in eGFP-expressing mice with and without enhanced oxygenation. BMC Cancer. 12:21. doi:10.1186/1471-2407-12-21 PDF
Principles of Biology Copyright © 2017 by Lisa Bartee, Walter Shriner, and Catherine Creech is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.
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12 Genetic Engineering
Walter Suza; Donald Lee; Marjorie Hanneman; and Patricia Hain
- Define genetic engineering.
- List and briefly explain the five basic steps in genetic engineering. Describe why each is necessary.
- Identify the fundamental differences between genetically engineered crops and non-genetically engineered crops.
- Explain the limitations to traditional breeding that are overcome by genetic engineering.
- Identify the approximate length of time required to obtain a marketable transgenic crop line (complete the entire crop genetic engineering process).
The production of genetically engineered plants became possible after Bob Fraley and others succeeded to use Agrobacterium tumefaciens to transform plant cells with recombinant DNA in the early 1980s (Vasil, 2008a). Since this breakthrough in plant biotechnology, GM crops are now routinely developed and grown in many parts of the globe. Current statistics on adoption of genetically engineered crops in the U.S. can be found on the USDA Economic Research Service’s website.
Genetic engineering has been used successfully to develop novel genes of economic importance that can be used to improve the genetics of crop plants. Genetic engineering is the targeted addition of a foreign gene or genes into the genome of an organism. The genes may be isolated from one organism and transferred to another or may be genes of one species that are modified and reinserted into the same species. The new genes, commonly referred to as transgenes, are inserted into a plant by a process called transformation. The inserted gene holds information that will give the organism a trait (Figure 1).
Crop genetic improvement (plant breeding) is an important tool but has limitations. First, in conventional terms, genetic improvement can only be done between two plants that can sexually mate with each other. This limits the new traits that can be added to those that already exist in that species. Second, when plants are mated, (crossed), many traits are transferred along with the trait of interest including traits with undesirable effects on yield potential.
Genetic engineering, on the other hand, is not bound by these limitations. It physically removes the DNA from one organism and transfers the gene(s) for one or a few traits into another. Since crossing is not necessary, the ‘sexual’ barrier between species is overcome. Therefore, traits from any living organism can be transferred into a plant. This method is more specific in that a single trait can be added to a plant.
The overall process of genetic engineering. A basic explanation of the five steps for genetically engineering a crop is provided. The five steps are:
- Locating an organism with a specific trait and extracting its DNA.
- Cloning a gene that controls the trait.
- Designing a gene to express in a specific way.
- Transformation, inserting the gene into the cells of a crop plant.
- Cross the transgene into an elite background.
Step 1: DNA Extraction
The process of genetic engineering requires the successful completion of a series of five steps and discoveries. To better understand each of these, the development of Bt maize will be used as an example.
Before the genetic engineering process can begin, a living organism that exhibits the desired trait must be discovered. The trait for Bt maize (resistance to European corn borer) was discovered around 100 years ago. Silkworm farmers in the Orient had noticed that populations of silkworms were dying. Scientists discovered that a naturally occurring soil bacteria was causing the silkworm deaths. These soil bacteria, called Bacillus thuringiensis, or Bt for short, produced a protein that was toxic to silkworms, the Bt protein.
Although the scientists did not know it, they had made one of the first discoveries necessary in the process of making Bt corn. The same Bt protein found to be toxic to silkworms is also toxic to European corn borer because both insects belong to the Lepidoptera order. The production of the Bt protein in the bacteria is controlled by the bacteria’s genes.
To be able to work with the gene responsible for making the Bt toxin, scientists must extract DNA from the Bt bacteria (Figure 2). This is accomplished by taking a sample of bacteria containing the gene of interest and taking it through a series of steps that separate the DNA from the other parts of a cell.
Step 2: Gene Cloning
The second step of the genetic engineering process is gene cloning. During DNA extraction, all the DNA from the organism is extracted at once. This means the sample of DNA extracted from the Bacillus thuringiensis bacteria will contain the gene for the Bt protein, but also all the other bacterium’s genes. Scientists use gene cloning to separate the single gene of interest from the rest of the DNA extracted (Figure 2).
The next stages of genetic engineering will involve further study and experimentation with this gene. To do that, a scientist needs to have thousands of exact copies of it. This copying is also done during the gene cloning step.
Step 3: Gene Design
Gene design relies upon another major discovery. This was the ‘One gene One enzyme’ Theory first proposed by George W. Beadle and Edward L. Tatum in the 1940’s. Discoveries made during their research laid the groundwork for the theory that a single gene stores the information that directs the cell in how to produce a single enzyme (protein ). Therefore, there is a single gene that controls the production of the Bt protein. It is called the Bt gene.
Once a gene has been cloned (Figure 2), genetic engineers begin the third step, designing the gene to work once inside a different organism. This is done in a test tube by cutting the gene apart with restriction enzymes and replacing certain regions (Figure 3).
Scientists replaced the bacterial gene promoter with promoters turn on the Bt gene in selected parts of the plant or promoters that can always turn on the Bt gene in all tissues. As a result, the first Bt gene released was designed to produce a level of Bt protein lethal to European corn borer and to only produce the Bt protein in green tissues of the corn plant, (stems, leaves, etc.). Later, Bt genes were designed to produce the lethal level of protein in all tissues of a corn plant, (leaves, stems, tassel, ear, roots, etc.).
Plant transformation and tissue culture
The process of transformation involves the insertion of the desired transgene construct (Figure 5) into cells of the recipient plant species. In this process, scientists isolate tissue or cells from the cultivar they wish to transform and use one of several methods to insert the transgene into the tissue or cells. The transgene construct contains the following key features.
- A promoter that acts to turn the gene on and off in the cell . The CaMV 35s promoter from the cauliflower mosaic virus (CaMV) is commonly used in genetic engineering. Other types of promoters, such as, the nopaline synthase promoter (NOS-Pro) also may be used to express transgenes in plant tissues.
- A selectable marker that is used to select cells that successfully obtained the construct during the transformation process . In figure 4, the selectable marker in the construct is NPT II (Kanr) that controls resistance to the antibiotic kanamycin. The cells of the plant used for transformation will be grown on a media containing the antibiotic. Other selectable markers that have been used successfully in plants include genes controlling herbicide resistance.
- A terminator sequence , such as the nopaline synthase (NOS) is included to mark the end of the transgene sequence for proper expression in plant cells.
Two commonly used transformation methods include Agrobacterium tumefaciens-mediated transformation and biolistics transformation (aka gene gun ), commonly referred to as particle bombardment (Figure 5). The biolistics method involves the use of high pressure to propel tungsten or gold beads coated with DNA of the gene construct into plant cells.
Agrobacterium-mediated plant transformation
Crown galls are tumors of plants that arise at the site of infection by some species of the Agrobacterium. Agrobacteria do not enter the plant cells but transfer a DNA segment called T-DNA from their circular extra chromosomal tumor-inducing (Ti) plasmid into the genome of the host cells. Ti plasmids are maintained in Agrobacteria because a part of their T-DNA contains genes that encode unusual amino acids used by Agrobacterium. The T-DNA also encodes genes that affect host plant hormone physiology resulting in induced growth of the infected cells and tumor formation. Scientists took advantage of Agrobacterium’s ability to stably integrate its T-DNA into the plant genome for introducing rDNA into plant cells. They first removed the genes that cause tumor or crown gall disease in plants from the T-DNA and engineered the plasmid for replication in both Escherichia coli and Agrobacterium cells. The initial replication of the construct in E. coli is useful for verifying the presence of the cloned gene and increasing the quantity of construct DNA for subsequent uses, including sequencing and transformation into Agrobacterium.
The steps in Agrobacterium-mediated transformation of plants are described in Figure 6.
At present, very few host cells receive the construct during the transformation process. Each random insertion of the construct into the genome of plant cells is referred as an event. Useful events are rare because of the random nature of the transformation process. Selectable markers are very important because they allow the identification of the rare events (Figure 7). Scientists must screen many potential transformants to identify events that are useful for breeding.
From there, the new DNA may or may not be successfully inserted into a chromosome. The cells that do receive the new gene are called transgenic and are selected from those that are not transgenic (Figure 7). Many types of plant cells are totipotent meaning a single plant cell can develop into an entire plant. Therefore, each transgenic cell can then develop into an entire plant which has the transgene in every cell. The transgenic plants are grown to maturity in greenhouses and the seed they produce, which has inherited the transgene, is collected. The genetic engineer’s job is now complete. He/she will hand the transgenic seeds over to a plant breeder who is responsible for the final step.
Inheritance of a transgene in plants
Transformation is successful when a transgene is incorporated into one of the chromosomes. The cells that have only one copy of the transgene in their genomes are said to be hemizygous (hemi = half, zygous = zygote). Because the segregation in the progeny of a hemizygous plant is the same as for a heterozygous plant, the term heterozygous will be used in this course when referring to a plant that is not homozygous for the transgene. The trait will segregate in the progeny in the same manner as any other gene in the plant as illustrated below (Figure 8).
Step 5: Backcross Breeding
The fifth and final part of producing a genetically engineered crop is backcross breeding (Figure 9). Transgenic plants are crossed with elite breeding lines using traditional plant breeding methods to combine the desired traits of elite parents and the transgene into a single line. The offspring are repeatedly crossed back to the elite line to obtain a high-yielding transgenic line. The result will be a plant with a yield potential close to current hybrids that expresses the trait encoded by the new transgene .
The Process of Plant Genetic Engineering
The entire genetic engineering process is basically the same for any plant. The length of time required to complete all five steps from start to finish varies depending upon the gene, crop species, and available resources. It can take anywhere from 6-15+ years before a new transgenic hybrid is ready for release to be grown in production fields.
The tissue culture process of regenerating transgenic plants from callus may result in genetic variation that is not associated with the transgene. Also, the parent line used for transformation commonly is selected for the frequency with which useful events can be obtained and not its agronomic performance. Therefore, transgenes are incorporated into commercial cultivars by conventional breeding procedures, such as backcrossing.
Genetic engineering is the directed addition of foreign DNA (genes) into an organism.
Five basic steps in crop genetic engineering:
- DNA extraction – DNA is extracted from an organism known to have the desired trait.
- Gene cloning – The gene of interest is located and copied.
- Gene modification – The gene is modified to express in a desired way by altering and replacing gene regions.
- Transformation – The gene(s) are delivered into tissue culture cells, using one of several methods, where hopefully they will land in the nucleus and insert into a chromosome.
- Backcross breeding – Transgenic lines are crossed with elite lines to make highyielding transgenic lines.
Vasil, I. K. (2008) A short history of plant biotechnology. Phytochem 7: 387-394.
Vasil, I. K. (2008) A history of plant biotechnology: from the Cell Theory of Shleiden and Schwann to biotech crops. Plant Cell Rep 27: 1423-1440.
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Professor Saltzman introduces the elements of molecular structure of DNA such as backbone, base composition, base pairing, and directionality of nucleic acids. He describes the processes of DNA synthesis, transcription, RNA splicing, translation, and post-translational processing required to make a protein such as insulin from its genetic code (DNA). Professor Saltzman describes the genetic code. RNA interference is also discussed as a way to control gene expression, which can be applied as a new way to treat diseases.
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National Research Council (US) Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health. Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. Washington (DC): National Academies Press (US); 2004.
Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects.
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2 Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms
This chapter provides a brief description of genetic modification methods used to develop new plant, animal, and microbial strains for use as human food. The next chapter ( Chapter 3 ) presents a detailed analysis of the likelihood for these methods to result in unintentional compositional changes.
Modification to produce desired traits in plants, animals, and microbes used for food began about 10,000 years ago. These changes, along with natural evolutionary changes, have resulted in common food species that are now genetically different from their ancestors.
Advantageous outcomes of these genetic modifications include increased food production, reliability, and yields; enhanced taste and nutritional value; and decreased losses due to various biotic and abiotic stresses, such as fungal and bacterial pathogens. These objectives continue to motivate modern breeders and food scientists, who have designed newer genetic modification methods for identifying, selecting, and analyzing individual organisms that possess genetically enhanced features.
For plant species, it can take up to 12 years to develop, evaluate, and release a new variety of crop in accordance with international requirements, which specify that any new variety must meet at least three criteria: it must be genetically distinct from all other varieties, it must be genetically uniform through the population, and it must be genetically stable (UPOV, 2002).
While advances in modification methods hold the potential for reducing the time it takes to bring new foods to the marketplace, an important benefit of a long evaluation period is that it provides opportunities for greater assurance that deleterious features will be identified and potentially harmful new varieties can be eliminated before commercial release. As discussed more fully in Chapter 5 , it is both prudent and preferable to identify potentially hazardous products before they are made commercially available, and with few exceptions standard plant breeding practices have been very successful in doing so.
- PLANT GENETIC MODIFICATION
Techniques Other than Genetic Engineering
The easiest method of plant genetic modification (see Operational Definitions in Chapter 1 ), used by our nomadic ancestors and continuing today, is simple selection. That is, a genetically heterogeneous population of plants is inspected, and “superior” individuals—plants with the most desired traits, such as improved palatability and yield—are selected for continued propagation. The others are eaten or discarded. The seeds from the superior plants are sown to produce a new generation of plants, all or most of which will carry and express the desired traits. Over a period of several years, these plants or their seeds are saved and replanted, which increases the population of superior plants and shifts the genetic population so that it is dominated by the superior genotype. This very old method of breeding has been enhanced with modern technology.
An example of modern methods of simple selection is marker-assisted selection, which uses molecular analysis to detect plants likely to express desired features, such as disease resistance to one or more specific pathogens in a population. Successfully applying marker-assisted selection allows a faster, more efficient mechanism for identifying candidate individuals that may have “superior traits.”
Superior traits are those considered beneficial to humans, as well as to domesticated animals that consume a plant-based diet; they are not necessarily beneficial to the plant in an ecological or evolutionary context. Often traits considered beneficial to breeders are detrimental to the plant from the standpoint of environmental fitness. For example, the reduction of unpalatable chemicals in a plant makes it more appealing to human consumers but may also attract more feeding by insects and other pests, making it less likely to survive in an unmanaged environment. As a result, cultivated crop varieties rarely establish populations in the wild when they escape from the farm. Conversely, some traits that enhance a plant's resistance to disease may also be harmful to humans.
Crossing occurs when a plant breeder takes pollen from one plant and brushes it onto the pistil of a sexually compatible plant, producing a hybrid that carries genes from both parents. When the hybrid progeny reaches flowering maturity, it also may be used as a parent.
Plant breeders usually want to combine the useful features of two plants. For example, they might add a disease-resistance gene from one plant to another that is high-yielding but disease-susceptible, while leaving behind any undesirable genetic traits of the disease-resistant plant, such as poor fertility and seed yield, susceptibility to insects or other diseases, or the production of antinutritional metabolites.
Because of the random nature of recombining genes and traits in crossed plants, breeders usually have to make hundreds or thousands of hybrid progeny to create and identify those few that possess useful features with a minimum of undesirable features. For example, the majority of progeny may show the desired disease resistance, but unwanted genetic features of the disease-resistant parent may also be present in some. Crossing is still the mainstay of modern plant breeding, but many other techniques have been added to the breeders' tool kit.
Interspecies crossing can take place through various means. Closely related species, such as cultivated oat ( Avena sativa ) and its weedy relative wild oat ( Avena fatua ), may cross-pollinate for exchange of genetic information, although this is not generally the case. Genes from one species also can naturally integrate into the genomes of more distant relatives under certain conditions. Some food plants can carry genes that originate in different species, transferred both by nature and by human intervention. For example, common wheat varieties carry genes from rye. A common potato, Solanum tuberosum , can cross with relatives of other species, such as S . acaule (Kozukue et al., 1999) or S . chacoense (Sanford et al., 1998; Zimnoch-Guzowska et al., 2000).
Chromosome engineering is the term given to nonrecombinant deoxyribonucleic acid (rDNA) cytogenetic manipulations, in which portions of chromosomes from near or distant species are recombined through a natural process called chromosomal translocation. Sears (1956, 1981) pioneered the human exploitation of this process, which proved valuable for transferring traits that were otherwise unattainable, such as pest or disease resistance, into crop species. However, because transferring large segments of chromosomes also transferred a number of neutral or detrimental genes, the utility of this technique was limited.
Recent refinements allow plant breeders to restrict the transferred genetic material, focusing more on the gene of interest (Lukaszewski, 2004). As a result, chromosome engineering is becoming more competitive with rDNA technology in its ability to transfer relatively small pieces of DNA. Several crop species, such as corn, soybean, rice, barley, and potato, have been improved using chromosome engineering (Gupta and Tsuchiya, 1991).
Sometimes human technical intervention is required to complete an interspecies gene transfer. Some plants will cross-pollinate and the resulting fertilized hybrid embryo develops but is unable to mature and sprout. Modern plant breeders work around this problem by pollinating naturally and then removing the plant embryo before it stops growing, placing it in a tissue-culture environment where it can complete its development. Such embryo rescue is not considered genetic engineering, and it is not commonly used to derive new varieties directly, but it is used instead as an intermediary step in transferring genes from distant, sexually incompatible relatives through intermediate, partially compatible relatives of both the donor and recipient species.
Recent advances in tissue-culture technologies have provided new opportunities for recombining genes from different plant sources. In somatic hybridization, a process also known as cell fusion, cells growing in a culture medium are stripped of their protective walls, usually using pectinase, cellulase, and hemicellulase enzymes. These stripped cells, called protoplasts , are pooled from different sources and, through the use of varied techniques such as electrical shock, are fused with one another.
When two protoplasts fuse, the resulting somatic hybrid contains the genetic material from both plant sources. This method overcomes physical barriers to pollen-based hybridization, but not basic chromosomal incompatibilities. If the somatic hybrid is compatible and healthy, it may grow a new cell wall, begin mitotic divisions, and ultimately grow into a hybrid plant that carries genetic features of both parents. While protoplast fusions are easily accomplished, as almost all plants (and animals) have cells suitable for this process, relatively few are capable of regenerating a whole organism, and fewer still are capable of sexual reproduction. This non-genetic engineering technique is not common in plant breeding as the resulting range of successful, fertile hybrids has not extended much beyond what is possible using other conventional technologies.
Somaclonal variation is the name given to spontaneous mutations that occur when plant cells are grown in vitro. For many years plants regenerated from tis-sue culture sometimes had novel features. It was not until the 1980s that two Australian scientists thought this phenomenon might provide a new source of genetic variability, and that some of the variant plants might carry attributes of value to plant breeders (Larkin and Scowcroft, 1981).
Through the 1980s plant breeders around the world grew plants in vitro and scored regenerants for potentially valuable variants in a range of different crops. New varieties of several crops, such as flax, were developed and commercially released (Rowland et al., 2002). Molecular analyses of these new varieties were not required by regulators at that time, nor were they conducted by developers to ascertain the nature of the underlying genetic changes driving the variant features. Somaclonal variation is still used by some breeders, particularly in developing countries, but this non-genetic engineering technique has largely been supplanted by more predictable genetic engineering technologies.
Mutation Breeding: Induced Chemical and X-ray Mutagenesis
Mutation breeding involves exposing plants or seeds to mutagenic agents (e.g., ionizing radiation) or chemical mutagens (e.g., ethyl methanesulfonate) to induce random changes in the DNA sequence. The breeder can adjust the dose of the mutagen so that it is enough to result in some mutations, but not enough to be lethal. Typically a large number of plants or seeds are mutagenized, grown to reproductive maturity, and progeny are derived. The progeny are assessed for phenotypic expression of potentially valuable new traits.
As with somaclonal variation, the vast majority of mutations resulting from this technique are deleterious, and only chance determines if any genetic changes useful to humans will appear. Other than through varying the dosage, there is no means to control the effects of the mutagen or to target particular genes or traits. The mutagenic effects appear to be random throughout the genome and, even if a useful mutation occurs in a particular plant, deleterious mutations also will likely occur. Once a useful mutation is identified, breeders work to reduce the deleterious mutations or other undesirable features of the mutated plant. Nevertheless, crops derived from mutation breeding still are likely to carry DNA alterations beyond the specific mutation that provided the superior trait.
Induced-mutation crops in most countries (including the United States) are not regulated for food or environmental safety, and breeders generally do not conduct molecular genetic analyses on such crops to characterize the mutations or determine their extent. Consequently, it is almost certain that mutations other than those resulting in identified useful traits also occur and may not be obvious, remaining uncharacterized with unknown effects.
Worldwide, more than 2,300 different crop varieties have been developed using induced mutagenesis (FAO/IAEA, 2001), and about half of these have been developed during the past 15 years. In the United States, crop varieties ranging from wheat to grapefruit have been mutated since the technique was first used in the 1920s. There are no records of the molecular characterizations of these mutant crops and, in most cases, no records to retrace their subsequent use.
Several commercial crop varieties have been developed using cell selection, including varieties of soybeans (Sebastian and Chaleff, 1987), canola (Swanson et al., 1988), and flax (Rowland et al., 1989). This process involves isolating a population of cells from a so-called “elite plant” with superior agricultural characteristics. The cells are then excised and grown in culture. Initially the population is genetically homogeneous, but changes can occur spontaneously (as in somaclonal variation) or be induced using mutagenic agents. Cells with a desired phenotypic variation may be selected and regenerated into a whole plant. For example, adding a suitable amount of the appropriate herbicide to the culture medium may identify cells expressing a novel variant phenotype of herbicide resistance. In theory, all of the normal, susceptible cells will succumb to the herbicide, but a newly resistant cell will survive and perhaps even continue to grow. An herbicide-resistant cell and its derived progeny cell line thus can be selected and regenerated into a whole plant, which is then tested to ensure that the phenotypic trait is stable and results from a heritable genetic alteration. In practice, many factors influence the success of the selection procedure, and the desired trait must have a biochemical basis that lends itself to selection in vitro and at a cellular level.
Breeders cannot select for increased yield in cell cultures because the cellular mechanism for this trait is not known. The advantage of cell selection over conventional breeding is the ability to inexpensively screen large numbers of cells in a petri dish in a short time instead of breeding a similar number of plants in an expensive, large field trial conducted over an entire growing season.
Like somaclonal variation, cell selection has largely been superceded by recombinant technologies because of their greater precision, higher rates of success, and fewer undocumented mutations.
As noted in Chapter 1 , this report defines genetic engineering specifically as one type of genetic modification that involves an intended targeted change in a plant or animal gene sequence to effect a specific result through the use of rDNA technology. A variety of genetic engineering techniques are described in the following text.
Agrobacterium tumefaciens is a naturally occurring soil microbe best known for causing crown gall disease on susceptible plant species. It is an unusual pathogen because when it infects a host, it transfers a portion of its own DNA into the plant cell. The transferred DNA is stably integrated into the plant DNA, and the plant then reads and expresses the transferred genes as if they were its own. The transferred genes direct the production of several substances that mediate the development of a crown gall.
Among these substances is one or more unusual nonprotein amino acids, called opines. Opines are translocated throughout the plant, so food developed from crown gall-infected plants will carry these opines. In the early 1980s strains of Agrobacterium were developed that lacked the disease-causing genes but maintained the ability to attach to susceptible plant cells and transfer DNA.
By substituting the DNA of interest for the crown gall disease-causing DNA, scientists derived new strains of Agrobacterium that deliver and stably integrate specific new genetic material into the cells of target plant species. If the transformed cell then is regenerated into a whole fertile plant, all cells in the progeny also carry and may express the inserted genes. Agrobacterium is a naturally occurring genetic engineering agent and is responsible for the majority of GE plants in commercial production.
Klein and colleagues (1987) discovered that naked DNA could be delivered to plant cells by “shooting” them with microscopic pellets to which DNA had been adhered. This is a crude but effective physical method of DNA delivery, especially in species such as corn, rice, and other cereal grains, which Agrobacterium does not naturally transform. Many GE plants in commercial production were initially transformed using microprojectile delivery.
In electroporation, plant protoplasts take up macromolecules from their surrounding fluid, facilitated by an electrical impulse. Cells growing in a culture medium are stripped of their protective walls, resulting in protoplasts. Supplying known DNA to the protoplast culture medium and then applying the electrical pulse temporarily destabilizes the cell membrane, allowing the DNA to enter the cell. Transformed cells can then regenerate their cell walls and grow to whole, fertile transgenic plants. Electroporation is limited by the poor efficiency of most plant species to regenerate from protoplasts.
DNA can be injected directly into anchored cells. Some proportion of these cells will survive and integrate the injected DNA. However, the process is labor intensive and inefficient compared with other methods.
The genes of most plant and some animal (e.g., insects and fish) species carry transposons, which are short, naturally occurring pieces of DNA with the ability to move from one location to another in the genome. Barbara McClintock first described such transposable elements in corn plants during the 1950s (Cold Spring Harbor Laboratory, 1951). Transposons have been investigated extensively in research laboratories, especially to study mutagenesis and the mechanics of DNA recombination. However, they have not yet been harnessed to deliver novel genetic information to improve commercial crops.
Nontransgenic Molecular Methods of Manipulation
Genetic features can be added to plants and animals without inserting them into the recipient organism's native genome. DNA of interest may be delivered to a plant cell, expressing a new protein—and thereby a new trait—without becoming integrated into the host-cell DNA. For example, virus strains may be modified to carry genetic material into a plant cell, replicate, and thrive without integrating into the host genome. Without integration, however, new genetic material may be lost during meiosis, so that seed progeny may not carry or express the new trait.
Many food plants are perennials or are propagated by vegetative means, such as grafting or from cuttings. In these cases the virus and new genes would be maintained in subsequent, nonsexually generated populations. Technically such plants are not products of rDNA because there is no recombination or insertion of introduced DNA into the host genome. Although these plants are not GE, they do carry new DNA and new traits. No such products are known to be currently on the market in the United States or elsewhere. (See McHughen  for further information on genetic mechanisms used in plant improvement.)
- ANIMAL GENETIC MODIFICATION
Domestication and Artificial Selection
Modern breeds of livestock differ markedly from their ancestors as a result of breeding strategies. For example, milk production per cow has increased among Holstein dairy cattle. Similarly, breeding programs have resulted in lean, fast-growing pigs (Notter, 1999). Chickens from modern breeds each produce more than 250 eggs per year, approximately double that produced in 1950, again mainly due to genetic selection.
Established and emerging biotechnologies in animal agriculture include assisted reproductive technologies; use of naturally occurring hormones, such as recombinant bovine somatotropin; marker-assisted selection; biotechnologies to enhance reproductive efficiency without affecting the genome; and biotechnologies to enhance expression of desirable genes.
Assisted Reproductive Procedures
Modern breeds of livestock differ from their ancestors because the use of frozen semen for artificial insemination (AI), along with sire testing and sire selection, has markedly affected the genetic quality of livestock, especially dairy cattle. Select bulls are tested for fertility and judged on the basis of the milk that their daughters produce. A notable example is the milk from Holstein cows, which increased almost threefold between 1945 and 1995 (Majeskie, 1996) through a combination of AI using semen from select bulls and improved milk production management (Diamond, 1999; Hale, 1969). Using sophisticated statistical models to predict breeding values, sire testing and selection, crossbreeding, and marker-assisted selection, along with AI, have greatly advanced the production characteristics of livestock. It is expected that AI will continue to be an integral tool in animal production systems.
(Assisted reproductive and recombinant hormone technologies are discussed in detail in the accompanying subreport, Methods and Mechanisms of Genetic Manipulation and Cloning of Animals .)
Techniques Fundamental to Genetic Engineering in Livestock
Although the following are not methods to generate modifications per se, they are considered modern methods that support the overall breeding and selection system for propagating desired genotypes for animals expressing desired traits.
Embryo Recovery and Transfer and Superovulation
Embryo recovery and transfer allow valuable animals to contribute more offspring to the gene pool (Seidel, 1984). Embryos that are frozen and stored before being used to initiate a pregnancy result in 40,000 to 50,000 beef calves per year (NAAB, 2000). Emerging technologies will allow the sexing of semen and embryos to control the gender of the offspring. The production of single-sex sperm, by cell sorting X and Y sperm, will greatly benefit the livestock industries (Johnson, 2000).
In Vitro Maturation and Fertilization of Oocytes
Up to several thousand embryos can be produced using techniques for recovering and maturing immature eggs, or oocytes, in about one day in a medium containing hormones, and then fertilizing them with live sperm or injecting a single sperm or sperm head into their outer layers—either beneath the zona pellucida or directly into the cytoplasm. The resulting zygotes are cultured in vitro, usually to the blastocyst stage, before being transferred to recipient females (First, 1991). The commercial application of in vitro maturation and fertilization has resulted in as many as 4,000 calves being born in a single year (NAAB, 2000).
Splitting or bisecting embryos yields zygotic twins, or non-GE clones, that are genetically identical in both their nuclear and mitochondrial genes (Heyman et al., 1998). Maternal twins exhibit greater variation in phenotype than paternal twins with only one X chromosome. Further, there is the potential for differences in mitochondrial DNA distribution to affect phenotype.
These embryos are then placed in an empty zona pellucida and transferred to recipient females, which carry them to term. Through 2001, a total of 2,226 registered Holstein clones—754 males and 1,472 females—were produced from embryo splitting, with 1 to 2 percent of calves produced (NAAB, 2000).
Cloning as a technique, and the implications for predicting and assessing adverse health effects that may be associated with this technique, are addressed in the committee's subreport that follows this report.
Techniques employed to introduce novel genes into domestic animals are discussed in detail in the report Animal Biotechnology: Science Based Concerns (NRC, 2002). These transgenic approaches applicable to animals are summarized in the following text.
Accessing the Germline of Animals
Germline refers to the lineage of cells that can be genetically traced from parent to offspring. It is possible to access the germline of animals using one of five methods (NRC, 2002):
directly manipulating the fertilized egg after it has been implanted in the uterus;
manipulating the sperm that produces the zygote;
manipulating early embryonic tissue in place;
using embryonic stem cell lines in early embryos; and
manipulating cultured somatic cells to transfer their nuclei into enucleated oocytes.
Several of the methods used to transfect or introduce novel genes into animals are similar to those used for plants. Commonly used methods include:
- microinjection of DNA into the nucleus of anchored cells;
- electroporation, where DNA is introduced through cell membrane pores by pulsed electrical charges;
- polycationic neutralization of the cell membrane and the DNA to be introduced to improve passive uptake;
- lipofection, where DNA is; and
- sperm-mediated transfection, often used in conjunction with intracytoplasmic sperm injection or electroporation.
As is the case with plants, microinjection is a highly inefficient means of creating transgenic animals. For example, an incredibly small percentage of livestock embryos that undergo microinjection yield transgenic animals (Rexroad, 1994). Moreover, successfully microinjected transgenic animals do not necessarily pass their transgenes on to their offspring (NRC, 2002).
This method is similar to viral delivery methods used in plants in that virus strains are modified to carry genetic material into a cell. It differs in that after the novel DNA is delivered, the viral replication process integrates it into the host cell's genome.
The use of transposable elements in animal cells has not been completely developed. Although no active naturally occurring transposable elements have been found in mammals, those found in insects and fish are under investigation for potential use in animals.
Knock-In and Knock-Out Technology
Transgenic technology can also be used to create organisms that lack specific genes or those in which one existing gene has been replaced by another that has been engineered. The addition (“knock-in”) or deletion (“knock-out”) of specific gene functions through introduced mutations or genetic engineering based on homologous recombination has become commonplace in animals used for experimentation, such as mice. Although at present this technology is not efficient and thus not practical for use in generating knock-in or knock-out domestic animals, there are examples of its use in domestic sheep and pigs. (NRC, 2002).
Marker-assisted selection involves establishing a link between inheriting a desirable trait, such as milk yield, and segregating specific genetic markers that are coupled to that trait. Marker-assisted selection is important in animal breeding and selection strategies for studying complex traits governed by many genes (Georges, 2001). The use of this method is expected to increase exponentially as genome-sequencing projects identify greater numbers of useful, segregated markers for economically important traits.
Initially animals will be screened for genes that control simple traits that may be undesirable, such as horns in cattle or metabolic stress syndrome in pigs. In time, easily identifiable markers that accompany multiple genes controlling more complex traits, such as meat tenderness and taste, growth, offspring size, and disease resistance, will become available to improve animal health and production traits (Dekkers and Hospital, 2002).
Two notable examples can be found in sheep. One is the Booroola gene in which a single-nucleotide base change is responsible for the callipyge muscle hypertrophy phenotype—the only known example of polar over-dominance in a mammal (Freking et al., 2002). Another is introgression of the Booroola gene into the Awassi and the Assaf dairy breeds (Gootwine, 2001).
Sequencing genomes of animals that are important to agriculture will identify genes that influence reproductive efficiency. For example, a growth-hormonereceptor variant on bovine chromosome 20 affects the yield and composition of milk, and is expected to increase milk production by 200 kg per lactation and decrease milk fat from 4.4 percent to 3.4 percent (Fletcher, 2003).
Nontransgenic Methods of Animal Manipulation
Biotechnology can be used to modify endocrine function of domestic animals and affect reproduction, lactation, and growth. For example, in pigs and rats (Draghia-Akli et al., 2002) hypothalamic-specific expression of growth-hormone-releasing hormone is not essential since ectopic expression of a cloned DNA for this neuropeptide can be genetically driven by a synthetic muscle-specific transcriptional promoter to elicit increases in both growth hormone and insulin-like growth factor-I (Khan et al., 2002). This biotechnology has the potential, by using specific hormones and growth factors during critical developmental periods, to enhance uterine capacity and to increase milk production.
- GENETIC MODIFICATION OF MICROBES
Humans have used and genetically modified (GM) microbes for centuries to produce food. Wine, bread, and cheese are common examples of ancient foods, still popular today, that depend on microbial ingredients and activities. Endogenous populations of microbes, particularly bacteria and yeasts, are genetically varied enough to provide sufficiently different traits to allow the development of useful microbial strains through simple selection or induced mutation.
Microorganisms play significant roles in food production. They serve primary and secondary roles in food fermentation and in food spoilage, and they can produce enzymes or other metabolites used in food production and processing. Fermentations can be initiated and conducted completely by the bacterial populations that are endogenous to the raw materials being fermented. However, it is more reliable in terms of uniformity and predictability to intentionally introduce starter cultures to initiate the fermentation and, in some instances, to perform the complete fermentation process. Most fermented products now are prepared this way in industrialized countries.
The types of microorganisms that carry out food fermentations range from bacteria to molds and yeasts, but by far the most widely used organisms are lactic acid bacteria (LAB) and yeasts ( Sacchromyces cerevisiae ). Traditional genetic modification methods that have been employed—particularly for microbial starter cultures—include selection, mutagenesis, conjugation, and protoplast fusion, the last of which is analogous to somatic hybridization in plant systems.
Before molecular genetics was developed and applied to LAB, the most widely used genetic modification method was chemical- or ultra-violet-induced mutagenesis, followed by an enrichment or selection process for mutants with superior characteristics.
A second traditional approach, conjugation, relies on natural methods of genetic exchange whereby DNA is transferred from one strain to another. Conjugation can occur between LAB strains as well as between LAB and other bacteria (Steenson and Klaenhammer, 1987). Although the resulting strains could conceivably be labeled as recombinant, the fact that this process can occur naturally circumvents application of the GE organism's classification.
A less common, but still useful, method has been to use protoplast fusion to facilitate recombination between two strains with superior but unique characteristics, producing a strain that possesses the desired characteristics of both parents. Protoplast fusion was classically used as a mapping method in bacteria and only recently has been used successfully to produce strains of LAB with desired characteristics (Patnaik et al., 2002). It has, however, been successfully used for some time to generate yeast strains that produce a greater number of biochemical substrates for use in the fermentation process (Pina et al., 1986).
Given the number and combinations of desirable traits in starter culture organisms, producers have remained interested in developing improved starter cultures, using essentially two different approaches. The traditional approach has been to identify endogenous strains with desirable traits by conducting many small-scale fermentations. This type of trial-and-error approach is far from practical because, while productive, low throughput is a limiting factor in the success rate.
The second approach is to produce the desired traits in the laboratory using molecular genetic and genetic engineering techniques. With the burgeoning field of genomics and the public availability of hundreds of fully sequenced bacterial genomes, this approach has become highly attractive and efficient and is favored by industry. Its primary advantage is the precision with which starter culture strains can be engineered.
The most common method used to introduce recombinant DNA into microorganisms is transformation, whereby DNA of interest is introduced directly into recipient cells by making them permeable using chemical agents, enzymes, or electroporation. The first method developed for LAB was plasmid protoplast fusion, in which recipient cells are stripped of walls and subsequently fused with polyethylene glycol, trapping the newly introduced DNA between the cells (Kondo and McKay, 1984).
Electroporation was developed for LAB during the late 1980s and employs electrical currents to create pores in the cell envelope, allowing DNA from other sources to enter (Luchansky et al., 1988). This method is probably the most widely used for research due to its simplicity. However, it lacks efficiency in many different species.
Recombinant DNA also can be introduced into LAB using a technique called transduction, in which a bacteriophage is used to move DNA from one strain into another (Bierkland and Holo, 1993). Unlike transformation, transduction can be fraught with problems that cause deletions within the plasmid (known as transductional shortening that are typically of undefined length).
Microbial transformation is usually simpler and more efficient than transformation in higher organisms, and has been in use longer for the development of commercial strains. Academic research also has been able to scrutinize the molecular genetic effects of transformation in microbes to a much greater extent than it has in higher organisms. Principles gleaned from studies of microbes have proven instrumental in understanding analogous events in the molecular genetics of higher organisms.
- Bierkland NK, Holo H. 1993. Transduction of a plasmid carrying the cohesive end region from Lactococcus lactis bacteriophage LC3 . Appl Environ Microbiol 59:1966–1968. [ PMC free article : PMC182195 ] [ PubMed : 16348973 ]
- Cold Spring Harbor Laboratory. 1951. Cold Spring Harbor Symposium on Quantitative Biology XVI: Genes and Mutations . Online. Available at http://library .cshl.edu /symposia/1951/index.html . Accessed November 4, 2003.
- Dekkers JC, Hospital F. 2002. The use of molecular genetics in the improvement of agricultural populations . Nat Rev Genet 3:22–32. [ PubMed : 11823788 ]
- Diamond J. 1999. Guns, Germs, and Steel: The Fates of Human Societies . New York: WW Norton.
- Draghia-Akli R, Malone PB, Hill LA, Ellis KM, Schwartz RJ, Nordstrom JL. 2002. Enhanced animal growth via ligand-regulated GHRH mygenic-injectable vectors . FASEB J 16:426–428. [ PubMed : 11790726 ]
- FAO/IAEA (Food and Agriculture Organization of the United Nations/International Atomic Energy Agency). 2001. FAO/IAEA Mutant Varieties Database . Online. Available at http://www-infocris .iaea.org/MVD/ . Accessed January 1, 2003.
- First NL. 1991. New advances in reproductive biology of gametes and embryos . In: Petersen RA, editor; , McLaren A,, editor; First NL, editor. , eds. Animal Applications of Research in Mammalian Development: Cur rent Communications in Cell and Molecular Biology . Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press. Pp.1–21.
- Fletcher A, ed. 2003. Gene Identified to Regulate Milk Content and Yield . Online. FoodProductionDaily.com. Available at http: //foodproductiondaily .com/news/news-NG.asp?id=29318 . Accessed February 28, 2003.
- Freking BA, Murphy SK, Wylie AA, Rhodes SJ, Keele JW, Leymaster KA, Jirtle RL, Smith TP. 2002. Identification of the single base change causing the callipyge muscle hypertrophy phenotype, the only known example of polar overdominance in mammals . Genome Res 12:1496–1506. [ PMC free article : PMC187527 ] [ PubMed : 12368241 ]
- Georges M. 2001. Recent progress in livestock genomics and potential impact on breeding programs . Theriogenology 55:15–21. [ PubMed : 11198079 ]
- Gootwine E. 2001. Genetic and economic analysis of introgression of the B allele of the FecB (Booroola) gene into the Awassi and Assaf dairy breeds . Livest Prod Sci 71:49–58.
- Gupta PK, Tsuchiya T. 1991. Chromosome Engineering in Plants: Genetics, Breeding Evolution . Amsterdam: Elsevier.
- Hale EB. 1969. Domestication and the evolution of behavior . In: Hafez ESE, editor. , ed. The Behavior of Domestic Animals . Baltimore: Williams & Wilkins. Pp.22–24.
- Heyman Y, Vignon X, Chesne P, Le Bourhis D, Marchal J, Renard JP. 1998. Cloning in cattle: From embryo splitting to somatic nuclear transfer . Reprod Nutr Dev 38:595–603. [ PubMed : 9932293 ]
- Johnson LA. 2000. Sexing mammalian sperm for production of offspring: The state-of-the-art . Anim Reprod Sci 60–61:93–107. [ PubMed : 10844187 ]
- Khan AS, Fiorotto ML, Hill LA, Malone PB, Cummings KK, Parghi D, Schwartz RJ, Smith RG, Draghia-Akli R. 2002. Maternal GHRH plasmid administration changes pituitary cell lineage and improves progeny growth of pigs . Endocrinology 143:3561–3567. [ PubMed : 12670834 ]
- Klein TM, Wolf ED, Wu R, Sanford JC. 1987. High velocity microprojectiles for delivering nucleic acids into living cells . Nature 327:70–73. [ PubMed : 1422046 ]
- Kondo JK, McKay LL. 1984. Plasmid transformation of Streptococcus lactis protoplasts: Optimization and use in molecular cloning . Appl Environ Microbiol 48:252–259. [ PMC free article : PMC241498 ] [ PubMed : 6091544 ]
- Kozukue N, Misoo S, Yamada T, Kamijima O, Friedman M. 1999. Inheritance of morphological characters and glycoalkaloids in potatoes of somatic hybrids between dihaploid Solanum acaule and tetraploid Solanum tuberosum . J Agric Food Chem 47(10):4478-4483. [ PubMed : 10552837 ]
- Larkin P, Scowcroft W. 1981. Somaclonal variation: A novel source of variability from cell culture for plant improvement . Theor Appl Genet 60:197–204. [ PubMed : 24276737 ]
- Luchansky JB, Muriana PM, Klaenhammer TR. 1988. Application of electroporation for transfer of plasmid DNA to Lactobacillus, Lactococcus, Leuconostoc, Listeria, Pediococcus, Bacillus, Staphylococcus, Enterococcus, and Propionibacterium . Mol Microbiol 2:637–646. [ PubMed : 3185282 ]
- Lukaszewski AJ. 2004. Chromosome manipulation and crop improvement . In: Encyclopedia of Plant and Crop Science . New York: Marcel Dekker.
- Majeskie JL. 1996. Status of United States dairy cattle . In: National Cooperative Dairy Herd Im provement Program, Fact Sheet K-7 . Washington, DC: U.S. Department of Agriculture.
- McHughen A. 2000. Pandora's Picnic Basket: The Potential and Hazards of Genetically Modified Foods . New York: Oxford University Press.
- NAAB (National Association of Animal Breeders). 2000. Breakthroughs in Biotechnology: Research Equips Producers with an Array of Genetic Improvement Tools . Online. Available at http://www .naab-css.org /education/biotech.html . Accessed February 17, 2003.
- Notter DR. 1999. The importance of genetic diversity in livestock populations of the future . J Anim Sci 77:61–69. [ PubMed : 10064028 ]
- NRC (National Research Council). 2002. Animal Biotechnology: Science-Based Concerns . Washington, DC: The National Academies Press. [ PubMed : 25032294 ]
- Patnaik RS, Louie S, Gavrilovic V, Perry K, Stemmer WPC, Ryan CM, del Cardayre S. 2002. Genome shuffling of Lactobacillus for improved acid tolerance . Nat Biotechnol 20:707–712. [ PubMed : 12089556 ]
- Pina A, Calderon IL, Benitex T. 1986. Intergeneric hybrids of Saccharomyces cerevisiae and Zygosaccharomyces fermentati obtained by protoplast fusion . Appl Environ Microbiol 51:995–1003. [ PMC free article : PMC239000 ] [ PubMed : 3089152 ]
- Rexroad CE. 1994. Transgenic farm animals . ILAR J 36:5–9.
- Rowland GG, McHughen AG, Bhatty RS. 1989. Andro flax . Can J Plant Sci 69:911–913.
- Rowland GG, McHughen AG, Hormis YA, Rashid KY. 2002. CDC Normandy flax . Can J Plant Sci 82: 425–426.
- Sanford LL, Kowalski SP, Ronning CM, Deahl KL. 1998. Leptines and other glycoalkaloids in tetraploid Solanum tuberosum × Solanum chacoense F2 hybrid and backcross families . Am J Potato Res 75:167–172.
- Sears ER. 1956. The transfer of leaf rust from Ae. umbellulata to wheat . Brookhaven Symp Biol 9:1–22.
- Sears ER. 1981. Transfer of alien genetic material to wheat . In: Evans LT, editor; , Peacock WJ, editor. , eds. Wheat Science, Today and Tomorrow . Cambridge: Cambridge University Press. Pp.75–89.
- Sebastian SA, Chaleff RS. 1987. Soybean mutants with increased tolerance for sulfonylurea herbicides . Crop Sci 27:948–952.
- Seidel GE Jr. 1984. Applications of embryo transfer and related technologies to cattle . J Dairy Sci 67:2786–2796. [ PubMed : 6394629 ]
- Steenson LR, Klaenhammer TR. 1987. Conjugal transfer of plasmid DNA between Streptococci immobilized in calcium alginate gel beads . Appl Environ Microbiol 53:898–900. [ PMC free article : PMC203777 ] [ PubMed : 3579288 ]
- Swanson EB, Couman MP, Brown GL, Patel JD, Beversdorf WD. 1988. The characterization of herbicide tolerant plants in Brassica napus L after in vitro selection of microspores and protoplasts . Plant Cell Rep 2:83–87. [ PubMed : 24241538 ]
- UPOV (International Union for the Protection of New Varieties of Plants). 2002. General Introduc tion to the Examination of Distinctness, Uniformity, and Stability, and the Development of Harmonized Descriptions of New Varieties of Plants . Online. Available at http://www .upov.int/en /publications/tg-rom/tg001/tg_1_3.pdf . Accessed December 12, 2003.
- Zimnoch-Guzowska E, Marczewski W, Lebecka R, Flis B, Schafer-Pregl R, Salamini F, Gebhardt C. 2000. QTL analysis of new sources of resistance to Erwinia carotovora ssp. atroseptica in potato done by AFLP, RFLP, and resistance-gene-like markers . Crop Sci 40:1156–1167.
- Cite this Page National Research Council (US) Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health. Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. Washington (DC): National Academies Press (US); 2004. 2, Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms.
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- Genetic Engineering
Genetic Engineering [UPSC Notes]
Genetic engineering, also called genetic modification, is the direct manipulation of an organism’s genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. Read important facts about Genetic Engineering in this article for the IAS Exam .
What is Genetic Engineering
- In simple words, genetic engineering can be described as the manual addition of a new DNA into an organism.
- It aids the addition of such traits that are not originally found in the organisms.
- Recombinant DNA is required to create Genetically Modified Organisms (GMO.)
- An area of chromosome (gene) is spliced.
- Genetic disorders in humans can be corrected using genetic engineering.
- Selective breeding has been in the world since ancient times.
- Jack Williamson used the word ‘Genetic Engineering’ in his science fiction novel Dragon’s Island which was published in 1951.
- First recombinant DNA molecules were created by an American Biochemist, Paul Berg.
New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA and then inserting this construct into the host organism. Genes may be removed, or “knocked out”, using a nuclease. Gene targeting is a different technique that uses homologous recombination to change an endogenous gene and can be used to delete a gene, remove exons, add a gene, or introduce point mutations.
Aspirants reading, ‘GEAC’ can also refer to topics lined below:
Applications of Genetic Engineering
Medicine, research, industry and agriculture are a few sectors where genetic engineering applies. It can be used on various plants, animals and microorganisms. The first microorganism to be genetically modified is bacteria.
- Manufacturing of drugs
- Creation of model animals that mimic human conditions and,
- Gene therapy
- Human growth hormones
- Follicle-stimulating hormones
- Human albumin
- Monoclonal antibodies
- Antihemophilic factors
- In Research: Genes and other genetic information from a wide range of organisms can be inserted into bacteria for storage and modification, creating genetically modified bacteria in the process.
- Transformation of cells in organisms with a gene coding to get a useful protein.
- Medicines like insulin, human growth hormone, and vaccines, supplements such as tryptophan, aid in the production of food (chymosin in cheese making) and fuels are produced using such techniques.
- Genetically modified crops are produced using genetic engineering in agriculture.
- Such crops are produced that provide protection from insect pests.
- It is used or can be used in the creation of fungal and virus-resistant crops.
- Natural area management
- Microbial art
Benefits of Genetic Engineering
- The production of genetically modified crops is a boon to agriculture.
- The crops that are drought-resistant, disease-resistant can be grown with it.
- As described earlier, genetic disorders can be treated.
- The diseases such as malaria, dengue can be eliminated by sterilising the mosquitoes using genetic engineering.
- Therapeutic cloning
Challenges of Genetic Engineering
- The production of genetically-engineered entities may result in an adverse manner and produce undesired results which are unforeseen.
- With the introduction of a genetically-engineered entity into one ecosystem for a desirable result, may lead to distortion of the existing biodiversity.
- Genetically-engineered crops can also produce adverse health effects.
- The concept of genetic-engineering is debated for its bioethics where community against it argue over the right of distorting or moulding the nature as per our needs.
Regulations in India
Genetic Engineering Appraisal Committee (GEAC) is the biotech regulator in India. It is created under the Ministry of Environment and Forests. Read more about GEAC in the linked article.
There are five bodies that are authorized to handle rules noted under Environment Protection Act 1986 “Rules for Manufacture, Use, Import, Export and Storage of Hazardous Microorganisms/Genetically Engineered Organisms or Cells 1989”. These are:
- Institutional Biosafety Committees (IBSC)
- Review Committee of Genetic Manipulation (RCGM)
- Genetic Engineering Approval Committee (GEAC)
- State Biotechnology Coordination Committee (SBCC) and
- District Level Committee (DLC)
Which are the genetically modified crops in India?
- Bt Cotton is the genetically modified crop that is under cultivation in India.
- Bt Brinjal was initially approved but later was blocked from production.
- GM Mustard is yet to be allowed for cultivated. It will be the first genetically modified food crop in the country.
FAQ about Genetic Engineering
What are some examples of genetic engineering, what are the pros and cons of genetic engineering.
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Prime purpose of this lecture is to present on Genetic Engineering. Genetic Engineers can alter the DNA code of living organisms. Genetic engineering (GE) is the modification of an organism’s genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species. Here briefly present on: Selective Breeding; Recombinant DNA; PCR; Gel Electrophoresis and Transgenic Organisms in terms of Genetic Engineering.
Reproductive Systems: Male and Female
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- Engineering /
Genetic Engineering Courses
- Updated on
- Jan 29, 2022
Medical Science is a significant spectrum that has been heavily impacted by the advancements in technology. When researchers combined Biology with the progressing technologies, it gave birth to the wide-ranging field of Biotechnology and revolutionized the science of medicine. With new emerging fields, Biology has sprouted into several branches that are thriving to bring inventiveness to the world of Medical Science. One such lesser-known branch of Biology is Genetic Engineering which blends the science of Biotechnology and Genetics. It utilizes Biotechnology for facilitating direct manipulation of a particular organism’s genes. If you are passionate about how genetics and technology can revolutionize the way we perceive medical science, you can choose from the several Genetic Engineering courses offered around the world. In this blog, we will discover the world of Genetic Engineering, its central elements along with the programs offered in this field across the globe.
Genetic Engineering is a field of Biology that deals with the manipulation of DNA and genes of an organism through Biotechnology in order to alter or modify a certain characteristic of an organism. An organism’s genes are manipulated through artificial synthesis or entering a new DNA strand to the already existing genes of an organism in order to change a specific function or characteristic of that organism. These genetically modified organisms are then used for various purposes, for example, a plant can be genetically modified in order to produce fruits that have a longer shelf life. Genetic Engineering has done some groundbreaking research in the field of Agriculture and was one of the key factors in the green revolution.
Syllabus of Genetic Engineering Courses
Pursuing a course in Genetic Engineering, you will get to learn about the theoretical as well as the practical aspects of both biology and technology. Before selecting a course, it is important to know its central elements that you will be studying. So here are the major subjects covered in Genetic Engineering Courses:
Biochemistry can be referred to as the branch of Biology that deals with the chemical aspects of any biological process. Biochemistry is an important branch of science in contemporary research because of the advent of synthetic substitutes instead of organic materials. This substitution has affected the health sector as well as the Microbiology sector and brought significance to the field of Biochemistry.
Immunology is the study of the immune system of an organism and how it defends itself from parasites and other disease-causing organisms. Immunology is an essential part of Microbiology because some of the fatal diseases that the human body suffers from, are caused by bacteria, viruses and other microorganisms. Immunology helps in determining the damage caused by these organisms and works on developing a cure for these diseases and preventing them in the future.
This is an interdisciplinary subject that combines Biology, Computer Application and Mathematics to understand biological data. This field is used mainly to assess biological data and identify the valid and necessary elements required to conduct a research. This field is extensively used for the identification of candidate genes to be used in an experiment.
Nanotechnology is another interdisciplinary field that is a crucial part of Genetic Engineering and is concerned with the manipulation of matter at a molecular or atomic scale. This field is used in Genetic Engineering to look at various processes involved in healthcare. Nanotechnology and Genetic Engineering are two core fields that have worked intensively to improve the health sector.
Genetic Engineering Courses: Eligibility Criteria
An individual aspiring to pursue a professional degree in Genetic Engineering can begin the BTech course after his/her 10 + 2 science with Physics, Chemistry, Maths, and Biology. Admission to BTech in Genetic Engineering is made through entrance tests conducted in-house by various universities or through the scores of the national engineering entrance examination like JEE for IITs/NITs & CFTI’s across the country.
Specializations Offered in Genetic Engineering
Here is a list of key specializations offered in the varied programs in the field of Genetic Engineering:
- Plant Tissue Culture
- Gene Therapy
- Stem Cell Biology
- Molecular Biology
Top Genetic Engineering Colleges in the World
Before we delve deep into the salient features of different colleges and shed light on their courses, let us take a quick look over the best Genetic Engineering colleges in the world:
Top Genetic Engineering Colleges in India
Here is yet another list of top genetic engineering colleges that can be found in India.
- SRM University Chennai, Tamil Nadu
- Bharath University Chennai, Tamil Nadu
- Aryabhatta Knowledge University, Patna, Bihar
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka
- Mahatma Jyoti Rao Phoole University, Jaipur, Rajasthan
- Bharath Institute of Science and Technology, Chennai, Tamil Nadu
- Indian Institute of Science, Bangalore, Karnataka
- Kuvempu University, Karnataka
- Madurai Kamaraj University, Tamil Nadu
- School of Engineering and Technology (SET), Sharda University, Greater Noida
Following are the minimum and maximum fees for UG, PG, and Doctoral levels:
Following are the required skillsets for Genetic engineers or Geneticists include:
- Strong understanding of scientific methods and rules
- PERL, Python
- Ability to use computer-aided design (CAD)
- Complex problem solving and critical thinking
- Graphics or photo imaging
- Word processing software programs
- Excellent mathematical, deductive and inductive reasoning, reading, writing, and oral comprehensive skills
- Ability to use lasers spectrometers, light scattering equipment, binocular light compound microscopes, etc.
Some of the major industries offering recruitment to Genetic Engineering are:
- Aurbindo Pharma
- Fresenius Medical Care
- The National Institute of Immunology
- Sun Pharmaceuticals Industries Ltd.
- Aspen Pharma
Job Profiles & Salary
Below are the job profiles with the given amount that is estimated and may differ depending on the experience, organization, or level of education:
NITs and IITs across India do not offer genetic engineering. But there are 2 – 3 colleges that take admission on the basis of JEE Main.
Switzerland, the USA, England, and Scotland are the few countries best for genetic engineering.
No, IIT directly does not offer genetic engineering. Candidates have to take life sciences in graduation or Biotechnology from any engineering college in India.
Thus, Genetic Engineering is a field that possesses the potential to change the future of Biotechnology and Medical Science. If you are planning to pursue Genetic Engineering courses, Leverage Edu experts can help in choosing an ideal course with the best-fit university with the help of our AI Course Finder . Book your free 30-minutes free consultation today!
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- Career in Genetic Engineer
Updated By Sakunth Kumar on 28 Sep, 2021 11:20 A.M
Last Updated On 25 Jun, 2020
How to Become a Genetic Engineer
About genetic engineer.
Genetic Engineering is one of the emerging fields in India, and the career prospects for the same are increasing. A scientist who changes DNA of living organisms through a laboratory technique is called a Genetic Engineer. A Genetic Engineer is also regarded as a Bio-technologist who plays a crucial role in using Genetic Techniques to manipulate genetic materials with an objective to develop new and improved living organisms. In all, a Genetic Engineer is directly related to the development and sustained survival of living organisms.
In India, the major emphasis is given to research and development in Genetic Engineering, and the person who is aspiring to become a Genetic Engineer will have to attain a higher-level degree, i.e., Ph.D to excel in this career. A Genetic Engineer works in a well-equipped laboratory. They use tools and technologies to examine the DNA structure. Most of their time is spent in research and experiment.
A Genetic Engineer job role has a huge impact on society. Their work can be used to cure genetic diseases, enhance the crops yield, improve the genetic structure of plants and other species etc.
You can check the detailed career prospects pertaining to Genetic Engineering here such as eligibility, job roles, pay scale etc.
Eligibility to become Genetic Engineer
In order to become a Genetic Engineering, the aspirants must have a relevant degree in the field. Most of the institutes offer M.Tech course in Genetic Engineering while the number of institutes offering B.Tech in the same is limited. Therefore, a candidate must complete a Bachelor’s degree in Science with specialization in Biophysics/ Biochemistry/ Molecular Biology/ Genetics. After attaining the relevant Bachelor’s degree, the candidates can either go for M.Sc in any of the above subjects or M.Tech or Master’s degree in Genetic Engineering. Obtaining an M.Tech degree will not be enough for the position of researcher or scientists. Therefore, a Ph.D in the respective field is mandatory.
Candidates enrolled in Ph.D will get a monthly stipend to finance or manage his/ her own education and personal expenses.
After acquiring a relevant degree, the candidate must initially get work experience as a supervisor, assistant, intern etc in a relevant field to get exposure to work. Later on, with some years of experience, they can apply for job roles in a specialized area.
Types of Job Roles Genetic Engineer
As Genetic Engineers mostly involved in research, they are often treated as Scientists. Therefore. There aren’t many job roles in the field of Genetic Engineering. A Genetic Engineer works in the laboratory as a Technician, Supervisor, Researcher, Scientist etc. The improvement in job positions depends on experience and skills. Here are some of the roles and responsibilities of Genetic Engineers -
- Examine DNA structures of organisms using modern tools and technologies
- Design and Execute Experiments
- Understand complex genetic structure.
- Manipulate or modify genes of plants, animals and other species including microorganism
- Help in the preparation of antibiotics,
- Handle hereditary diseases by studying the genetic structure of an organism.
Top Recruiting Sectors for Genetic Engineers
The career prospects in this field are spread across different sectors. They can be found working in different sectors which are listed below: -
- Research Centres
- Pharmaceutical Companies
- Government Agencies
Top Recruiting Companies/ Agencies/ Organizations for Genetic Engineers
Following are some of the organisations that hire a Genetic Engineer in India:
- Tata Institute for Genetics and Society
- ICGEB International Centre for Genetic Engineering and Biotechnology
- Tata Medical Center
Planning to choose Genetic Engineer as your career?
Pay scale/salary of genetic engineer.
The salary of a Genetic Engineer depends on so many factors like years of experience, skills, employer etc. The average starting salary of a Genetic Engineer in India is expected to be Rs 3.00 Lakhs per Annum. The pay scale increases with years of experience and skills.
The pay scale mentioned here is just indicative and expected to change unconditionally.
Books & Study Material to Become Genetic Engineer
Following are some of the best books related to Genetic Engineering: -
- Genetic Engineering by P.S Verma P.S, V.K Agarwal V.K
- An Introduction to Genetic Engineering by Desmond S. T. Nichol
- Genetic Engineering by Jane K. Setlow
- Biotechnology and Genetic Engineering by Lisa Yount
- Genetic Engineering (Oxford Higher Education) by Smita Rastogi, Neelam Pathak
Pros of becoming a Genetic Engineer
- The research and work carried out by a Genetic Engineer have a positive impact on agriculture as the yields of crops is maximized.
- A Genetic Engineer plays a major role to prevent genetic diseases in humans.
- A Genetic Engineer helps in the treatment of novel diseases caused by microorganisms,
- A Genetic Engineer plays a major role to develop stronger plants, healthier animals, and prevent diseases.
Cons of becoming a Genetic Engineer
- The Genetic Engineering technology research and work can cause severe problems to certain groups of people.
- Sometimes, the research and experiments can lead to the creation of viruses, pathogens that are harmful or risky.
- The research and experiments must be carried very carefully.
- There is a risk of negative impact on work. For example, plants and animals with birth defects and mutation can generate.
- There aren’t many job roles in this field as Genetic Engineers mostly involved in the research.
Top Colleges to pursue career as Genetic Engineer
Paths for being genetic engineer, do you think this is the right career choice for you.
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