4.3: Applications of Recombinant DNA Technology
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- 135670
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)In 2023, the U.S. Department of Agriculture (USDA) reported the slaughter of approximately 32 million cattle for the commercial meat market, making the U.S. is one of the largest beef producers in the world. More and more, people are beginning to become concerned about the use of animals for meat.
Enter recombinant DNA technology....
Today, recombinant DNA techniques are being used to engineer growth factors and other critical substance that help animal cells grow and multiply under lab conditions. These recombinant compounds mimic the natural environment found in the animal and can support the in vitro development of muscle and fat cells into edible tissue - i.e., lab-grown meat. New companies have since been created to take advantage of this emerging technology to produce commercial-grade cultured meat with the look, texture, and taste of farm-raised beef and chicken. While it may sound "gross", lab-grown meat has the potential to reduce the environmental impact of meat production and eliminate animal cruelty. Moreover, this meat can be tailored for better nutrition (e.g., less saturated fat, more omega-3s), minimizing the health impacts of meat consumption on humans.
Lab-grown meat? "Impossible" no longer.
Introduction
Recombinant DNA (rDNA) technology (i.e., DNA cloning) is a powerful biotechnology tool that allows scientists to manipulate DNA in order to create genetic combinations that do not occur naturally. Today, rDNA is a part of everyday life, without people being aware of it. In medicine, rDNA technology has been used to genetically modify bacteria and yeast, turning them into living "factories" of therapeutic proteins, like hormones and growth factors. In agriculture, rDNA has revolutionized farming by engineering crops to be more resistant to pests and drought, in addition to enhancing their nutritional content. In the food industry, rDNA is used to produce enzymes in food processing, providing more consistent, ethical, and cost-effective alternatives to animal-derived ingredients. Genetically-engineered microbes are used to produce biofuels by converting biomass into ethanol or other renewable energy sources, supporting cleaner energy solutions. In manufacturing, recombinant enzymes like proteases and amylases are incorporated into laundry detergents to improve stain removal and reduce the need for high-temperature washing. Plants engineered through recombinant DNA are used in environmental biotechnology to clean up pollutants from soil or water. With each passing year, how rDNA technology is being applied is becoming more and more varied.
Recombinant DNA (rDNA) technology has applications in a wide variety of fields, including that of medicine. At the end of this section, you will be able to:
- Explain some common applications for rDNA technology
Applications for Recombinant DNA Technology
rDNA and Medicine
In medicine, rDNA technology drives the development of numerous treatments that can be used in healthcare and medicine. Through its combination of DNA from different sources, rDNA technology is used in the production of therapeutic proteins, like hormones and growth factors, the development of vaccines and monoclonal antibodies. It is also at the heart of gene therapy research, where it holds promise for treating genetic disorders by correcting defective genes. To learn more about the use of rDNA in medical biotechnology, go to Chapter 10: Medical Biotechnology.
rDNA and Genetically Modified (GM) Crops
rDNA technology is used in the creation of genetically modified (GM) crops in order to insert desired genes into the genome of plants. The ultimate goal of this technology is to give crops new or enhanced traits that are not naturally present. Examples of genes used in the modification of crops are those that will confer insect resistance, drought tolerance, or improve nutrition. One of the most successful application of rDNA in the production of a GM crop is the production of "Bt crops" like Bt corn or Bt cotton. In these crops, a gene from the soil bacterium Bacillus thuringiensis is inserted into the plant. This gene enables the plant to produce a protein that is toxic to certain insect pests but safe for humans and animals, reducing the need for chemical pesticides. Similarly, herbicide-tolerant crops, such as glyphosate-resistant soybeans, have been engineered with rDNA to survive the application of weed-killing herbicides, making weed control more efficient. By using rDNA technology, these genetic modifications improve crop yields, reduce agricultural input costs, and contribute to more sustainable farming practices. To learn more about how rDNA technology is used in the genetic modification of plants go to Chapter 9: Agricultural and Environmental Biotechnology.
rDNA and Food Processing
rDNA technology is a key part of the food industry and its efficient, safe and ethical production of enzymes and additives. Instead of extracting these substances from animal or plant sources, scientists can insert the genes responsible for producing them into microbes like bacteria or yeast. These microbes can be used to easily and quickly mass-produce the desired compounds through fermentation. A well-known example is recombinant chymosin, an enzyme used in cheese-making. Traditionally obtained from calf stomachs, chymosin is now produced using genetically-modified E. coli or yeast that express the bovine chymosin gene. As a result, rDNA technology has made commercial cheese production more consistent, cost-effective, and suitable for vegetarians. In addition, rDNA is used to produce other enzymes like amylases, lipases, and proteases, which are used in commercial baking, brewing, and juice clarification. The end result of rDNA technology in food processing is improvements in food quality, shelf life, and processing efficiency while reducing reliance on animal sources and environmental impact.
rDNA and Biofuel Production
Today, rDNA technology is being used extensively to genetically-modify bacteria, yeast, or algae, to efficiently convert plant biomass into biofuels like bioethanol or biodiesel. One common approach is the introduction of the gene for cellulase into industrial strains of Saccharomyces cerevisiae (i.e., brewer’s yeast). The end result is a microbe capable of digesting cellulose—a component of plant cell walls that yeast can't normally can't break down—into simple sugars that are then fermented into bioethanol. Similarly, algae can be engineered with rDNA to enhance their production of lipids, which can then be processed into biodiesel. These approaches allow for the enzymatic breakdown and fermentation of biomass like agricultural waste (e.g., cornstalks, rice husks), forestry scraps (e.g., wood chips, sawdust), and municipal wastes (e.g., sewage) into biofuels, making biofuel production more sustainable, cost-effective, and offering cleaner alternatives to fossil fuels. The use of genetically-modified organisms in biofuel production is also decreasing the impact of biomass on the environment. For more information about microbes and biofuel production, go to Chapter 7: Microbial Biotechnology.
rDNA and Industrial Enzymes
rDNA technology is used in the production of industrial detergents by enabling the large-scale, cost-effective production of critical enzymes that improve cleaning performance. As an alternative natural sources for these enzymes, rDNA enables the genetic modification of microbes like E. coli, Bacillus subtilis, or yeast. These engineered microbes then produce specific enzymes through fermentation, which are harvested and added to detergents. Common recombinant enzymes used in industry include proteases, for the break down of protein-based stains (e.g., blood, egg), amylases to break down starches, lipases, for the break down fats and oils found in grease stains, and cellulases that remove "microfuzz" and brighten fabrics. Because these recombinant enzymes work more effectively at lower temperatures than their "natural" counterparts, they make detergents more energy-efficient and environmentally friendly. rDNA also allows manufacturers to design enzymes that are more stable in harsh washing conditions like high pH or the presence of bleach. To read more about industrial biotechnology, go to Chapter 11: Industrial Biotechnology.
rDNA and the Environment
rDNA has become an important part in bioremediation and its cleaning up of the environment. Genetically-engineered microbes and plants have been found to be very efficient at breaking down, absorbing, or neutralizing environmental pollutants such as heavy metals, oil spills, pesticides, plastics and industrial waste. These microbes can be combined with unmodified or "natural" organisms to enhance certain cleanup processes. For example, bacteria like Pseudomonas putida has been genetically-modified using rDNA to degrade common industrial pollutants, such as toluene and xylene. rDNA has been used to engineer microbes with enzymes that break down plastic, offering a potential solution to plastic pollution. Finally, genes that help bacteria tolerate or accumulate heavy metals like mercury, arsenic, or lead, can also be inserted, allowing these bacteria to clean-up contaminated water or soil. By tailoring the engineering of microbes to clean up specific contaminants, rDNA technology makes bioremediation faster, more targeted, and cost-effective. To learn more about how rDNA technology is used in bioremediation go to Chapter 9: Agricultural and Environmental Biotechnology.
Recombinant DNA technology can be applied to a vast number of scientific fields, including agriculture, medicine, and industry. Some major concepts to remember are:
- common genetically-modified microbes include bacteria, yeast, and algae
- genetically-modified microbes are used to create therapeutic proteins, produce enzymes, and generate biofuels
- the use of genetically-modified microbes in the production of biofuels is helping to decrease the disposal of large amount of biomass
- genetically-modified crops are revolutionizing the agriculture field by making crops more tolerant to pests, pesticides, and harsh environmental conditions
- genetically-modified organisms are a key part of bioremediation, making this area more cost-effective and efficient
Glossary
Amylase - an enzyme that breaks down starches into simple sugars like glucose
Biofuel - a fuel made from biological materials (i.e., biomass); includes bioethanol and biodiesel
Biomass - organic material from plants or animals that is used as a renewable energy source
Bioremediation - the use of living organisms, like bacteria or plants, to clean up environmental pollutants
Cellulase - an enzyme that breaks down cellulose into glucose
Cellulose - a complex polysaccharide made up of repeating glucose molecules; found in the cell wall of plants and algae
Chymosin - an enzyme used in cheese-making to curdle milk
Genetically-modified (GM) crop - a crop whose DNA has been altered using genetic engineering techniques to introduce traits like pest resistance, herbicide tolerance, or improved nutritional content
Fermentation - a biological process where microbes (like bacteria and yeast) convert sugars into other products like alcohol, gases, or acids
Lipase - an enzyme that breaks down fats (i.e., lipids) into glycerol and fatty acids
Monoclonal antibodies - antibodies produced by clones of a single immune cell known as a B cell
Proteases - enzymes that break down proteins into amino acids
Recombinant DNA (rDNA) - DNA formed by combining genetic material from different sources
Therapeutic protein - a protein used as a treatment for disease, often produced using recombinant DNA
Vaccine - a biological preparation that stimulates the immune system to protect against a specific disease