Recombinant DNA: History and Applications

Recombinant DNA

• Recombinant DNA (rDNA) is DNA that has been artificially created by combining DNA from two different species.
• rDNA is often shortened to rDNA.
• It's a modified DNA strand made from combining two or more gene sequences. This combined sequence may or may not naturally occur.
• rDNA is engineered for a specific purpose to be used in one of the fields noted below.

History of Recombinant DNA

• Genetically engineered organisms began in the early 1970s, initiating the transfer of genes between bacteria of the same species (E. coli).
• In 1978, Cohen and colleagues advanced the technology, transferring an insulin synthesis gene to a plasmid of E. coli, thus creating the first genetically modified organism (GMO).
• By 1982, this protocol received regulatory approval from the US Food and Drug Administration, allowing for the mass production of human insulin.

Applications of Recombinant DNA

Agricultural Applications

• Distant Hybridization: Combines traits from different plant species.
• Transgenic Plants: Genetically modified plants containing foreign genes. (Example: Plants that resist pests or herbicides or produce certain compounds.)
• Development of C4 plants: These plants are more efficient in utilizing carbon dioxide for photosynthesis.

Medicinal Applications

• Production of antibiotics: Recombinant DNA technology produces important antibiotics.
• Production of hormone insulin: Enables mass production of human insulin for patients with diabetes .
• Production of vaccines: Vaccines for diseases are produced using rDNA technology.
• Production of interferons: Interferons are virus-induced proteins that act as a first line of defense against viruses and are crucial in treating various diseases.

Other Important Applications

• Production of enzymes: Useful enzymes such as urokinase, used to dissolve blood clots, can be produced using recombinant DNA technology.
• Gene therapy: Uses recombinant DNA technology to replace defective genes responsible for hereditary diseases with normal genes. (Example: Hemophilia, phenylketonuria, and alkaptonuria).
• Diagnosis of disease and disputes: DNA testing can determine genotypes of individuals and assess the likelihood of offspring inheriting genetic disorders. Also used in paternity testing.
• Production of transgenic animals: Animals with foreign genes introduced.
• Industrial applications: rDNA helps in producing valuable chemicals, improving fermentation processes, and utilizin9g waste products to create valuable proteins.

Genetic Engineering

• The process of using recombinant DNA technology to alter the genetic makeup of an organism.
• Traditionally involves controlling breeding and selecting offspring with desirable traits.
• Directly manipulates one or more genes; often, a gene from one species is added to another organism's genome to give it a desired phenotype.
• The resulting organisms are called transgenic or genetically modified organisms (GMO).
• Artificial modification of an organism's genetic composition is done by transferring genes from one organism to another of a different species to grant the latter species traits of the first organism.

Processes in Genetic Engineering

• DNA extraction: Isolating DNA from an organism.
• Gene cloning: Separating a specific gene from other DNA and generating copies of the sought after gene.
• Gene design: Modifying specific gene regions in a test tube with enzymes.
• Transformation: Introducing the designed DNA sequences into host cells.
• Backcross breeding: Process of crossing a genetically modified organism with a non-modified organism to produce an offspring with more of the desired modified trait.