Reference Material 3 - Recombinant DNA.pdf

SENIOR HIGH SCHOOL STEM02: General Biology 2 Refer...

SENIOR HIGH SCHOOL STEM02: General Biology 2 Reference Material #3 Learning Competencies 1. Explain DNA technology 2. Discuss the applications of recombinant DNA Learning Objectives 1. Discuss the process of Recombinant DNA Technology; and 2. Determine the implications of Recombinant DNA Technology in various fields; and 3. Evaluate the ethicality and issues surrounding the use of DNA Technology. DNA Technology DNA technology, also known as genetic engineering or biotechnology, refers to the methods and techniques used to manipulate and modify DNA (deoxyribonucleic acid) for various purposes. DNA is the genetic material found in the cells of all living organisms, and it carries the instructions necessary for an organism's growth, development, functioning, and reproduction. DNA technology involves a range of scientific and technological processes that allow scientists to study, manipulate, and even transfer genetic information between different organisms. This technology has numerous applications in various fields, including medicine, agriculture, forensics, and research. Some key aspects of DNA technology include: 1. Genetic Modification: DNA technology enables the alteration of an organism's genetic makeup by introducing new genes or modifying existing ones. This can result in the production of organisms with desired traits, such as disease resistance in crops or the production of therapeutic proteins in bacteria. 2. Recombinant DNA Technology: This involves combining DNA from different sources to create recombinant DNA molecules. These molecules can be inserted into host organisms to produce specific proteins or traits. Recombinant DNA technology is the basis for genetic engineering. 3. Cloning: DNA technology allows the creation of genetically identical copies of organisms, cells, or genes. Cloning can have applications in agricultural breeding, medical research, and conservation efforts. 4. Gene Editing: Techniques like CRISPR-Cas9 have revolutionized DNA technology by enabling precise editing of specific DNA sequences. This can lead to targeted modifications of genes, with potential applications in treating genetic disorders or creating genetically modified organisms (GMOs). 5. DNA Sequencing: DNA technology enables the determination of the precise order of nucleotides in a DNA molecule. This information is crucial for understanding genetic variations, studying diseases, and identifying genes associated with specific traits. 6. Genetic Testing and Diagnosis: DNA technology plays a vital role in diagnosing genetic disorders and diseases. Genetic testing involves analyzing an individual's DNA to identify mutations, variations, or markers associated with specific conditions. 7. Forensic Analysis: DNA technology is widely used in forensic science for identifying individuals based  on their DNA profiles. It has become a crucial tool in solving crimes and identifying human remains. 8. Biomedical Research: DNA technology allows researchers to study the genetic basis of diseases, develop new therapies, and understand the molecular mechanisms underlying various biological processes. 9. Agricultural Applications: DNA technology is used in agriculture to create genetically modified crops with improved traits, such as pest resistance or increased nutritional content. 10. Synthetic Biology: This interdisciplinary field involves designing and constructing new biological parts, devices, and systems using DNA technology. It has applications in creating new materials, biofuels, and even artificial organisms. DNA technology has profoundly impacted many aspects of modern life and continues to advance rapidly, leading to both ethical and societal considerations. Its potential benefits are far-reaching, but responsible and informed use is essential to ensure its applications are safe, ethical, and beneficial to humanity and the environment. Recombinant DNA Technology Recombinant DNA technology involves the manipulation of DNA to create new combinations of genetic material from different sources. This technology has revolutionized various fields by allowing scientists to introduce specific genes into host organisms, resulting in the production of desired traits or proteins. The process typically involves the following steps: a. DNA Isolation: The target gene of interest is isolated from the DNA of a donor organism using techniques like polymerase chain reaction (PCR) or restriction enzyme digestion. Enzymes that cut DNA at specific sequences, known as restriction enzymes, are used to generate DNA fragments. b. Vector Preparation: A vector, usually a plasmid or a viral DNA fragment, is prepared to carry the foreign DNA. The vector is often modified to include a promoter sequence that drives gene expression and a selectable marker for identifying transformed cells. c. DNA Ligation: The isolated gene is combined with the vector using DNA ligase, an enzyme that seals the DNA fragments together. This creates a recombinant DNA molecule with the foreign gene inserted into the vector. d. Transformation: The recombinant DNA molecule is introduced into a host organism's cells. This can be done through methods like heat shock, electroporation, or viral infection. The host organism then replicates the recombinant DNA as it reproduces. e. Expression and Selection: In some cases, the introduced gene is expressed to produce a desired protein. The selectable marker on the vector helps identify cells that have successfully taken up the recombinant DNA. These transformed cells are selected and grown in culture. f. Harvesting: The cells containing the desired gene product are harvested and processed to obtain the protein of interest. This protein can have applications in medicine, industry, agriculture, and research.  Steps of Recombination DNA Technology 1. Isolation of Genetic Material it must be separated and purified which involves enzymes such as lysozymes, cellulase, chitinase, ribonuclease, proteases etc. 2. Restriction Enzyme restriction enzymes act as molecular scissors that cut DNA at specific Digestion locations. 3. Amplification Using PCR helps to amplify a single copy or a few copies of DNA into thousands to millions of copies. 4. Ligation of DNA Molecules process of joining these two pieces together using the enzyme ‘DNA ligase’. 5. Insertion of Recombinant the recombinant DNA is introduced into a recipient host cell mostly, a DNA Into Host bacterial cell. 6. Isolation of Recombinant isolation of recombinant cell from non-recombinant cell, marker gene of Cells plasmid vector is employed. Implications of Recombinant DNA Technology Recombinant DNA technology has far-reaching implications in various fields: Medicine: It enables the production of therapeutic proteins, gene therapies, and genetically modified organisms for research. Agriculture: It allows the development of genetically modified crops with improved traits, such as pest resistance and enhanced nutritional content. Pharmaceuticals: It facilitates the production of pharmaceutical compounds, including insulin and vaccines, through recombinant protein expression. Biotechnology: It plays a key role in creating enzymes used in industrial processes, such as detergents and biofuels. Research: It enables the study of gene functions, regulation, and interactions, advancing our understanding of biology. There are many different traits that can be introduced to organisms to change their properties. The following table shows examples of modified traits using cloned genes and their applications: MODIFIED TRAIT GENE RECIPIENT APPLICATION MODIFICATION ORGANISM (FIELD) Insulin Production Insertion of Human Bacteria (Medicine) Insulin Gene Production of Human Insulin in Bacteria Pest Resistance Insertion of Bt-toxin gene Corn/Maize (Agriculture) Production of corn plants with increased resistance to corn boxer Delayed Ripening Disruption of a gene for a Tomato plant Agriculture) ripening enzyme (e.g. Production of plants with polygalacturonase) fruits that have delayed ripening fruits. These fruits will survive longer  transport time, allowing their delivery to further locations (i.e. export deliveries) Chymosin Production Insertion of a gene for Bacteria (Industry) chymosin Enhance large scale production of chymosin. This enzyme serves as a substitute for rennet in the coagulation of milk. Rennet has to be harvested from calves. The large scale production of this enzyme in bacteria provides an abundant supply of this important component for the cheese production industry. Recombinant DNA technology has led to the creation of numerous genetically modified organisms (GMOs) with diverse applications in various fields. Here are some examples of organisms that have been developed using recombinant DNA technology: 1. Insulin-Producing Bacteria: Example: Escherichia coli (E. coli) bacteria Application: Recombinant DNA technology has been used to insert the human insulin gene into E. coli bacteria. These bacteria then produce human insulin, which is harvested and used to treat individuals with diabetes. 2. Bt Cotton: Example: Cotton plants (Gossypium spp.) Application: Certain cotton varieties have been genetically modified to express the Bacillus thuringiensis (Bt) toxin, which is toxic to certain insect pests. This modification helps reduce the need for chemical pesticides. 3. Golden Rice: Example: Rice plants (Oryza sativa) Application: Golden rice has been engineered to produce beta-carotene, a precursor of vitamin A. This modification aims to address vitamin A deficiency, a common nutritional issue in many developing countries. 4. Salmon: Example: Atlantic salmon (Salmo salar) Application: A genetically modified salmon known as "AquAdvantage" salmon has been developed to grow faster due to the incorporation of a growth hormone gene from Chinook salmon and a promoter from ocean pout. 5. Papaya: Example: Papaya plants (Carica papaya) Application: Recombinant DNA technology was used to develop virus-resistant papaya varieties. These GMOs are resistant to the ringspot virus, a disease that can devastate papaya crops.  6. Tomato: Example: Tomato plants (Solanum lycopersicum) Application: Genetically modified tomatoes with extended shelf life have been developed by inhibiting the production of a protein responsible for softening. This modification can reduce post-harvest losses. 7. Agricultural Crops (Corn, Soybeans, Canola, etc.): Examples: Various crops like corn, soybeans, and canola have been genetically modified to exhibit traits such as herbicide resistance, insect resistance, and improved nutritional content. 8. Genetically Modified Organisms for Research: Examples: Mice, fruit flies, and other model organisms have been genetically modified to study specific genes and their functions. These organisms are vital for advancing our understanding of genetics and diseases. These examples highlight the versatility of recombinant DNA technology and its impact on various sectors, including medicine, agriculture, and biotechnology. However, it's important to note that GMOs often raise discussions about safety, ethical concerns, and potential environmental effects. Ethicality and Issues Recombinant DNA technology raises ethical concerns and issues, including: Genetic Engineering of Humans: The potential to edit human genes raises ethical dilemmas, such as altering the germline (inheritable changes) and designer babies. Environmental Impact: The release of genetically modified organisms into the environment has unknown ecological consequences. Ownership and Patents: Who owns genetically modified organisms and their components? Patents on genes and organisms can lead to controversies. Safety: Ensuring the safety of genetically modified organisms and their products is essential to prevent unintended consequences. Informed Consent: Ethical considerations arise in genetic testing, research, and therapy, especially regarding consent and privacy. Balancing the benefits of recombinant DNA technology with its ethical challenges requires responsible research, robust regulations, and informed public discourse.