Genetic Engineering History and Development

• List at least 5 products of Genetic Engineering in Medicine, Agriculture, Industry, Environment, etc.
• Explain why and how one product was engineered, along with its pros and cons.

Genetic Engineering

• Genetic engineering, also known as recombinant DNA technology and biotechnology, was coined in 1919 by Karl Ereky.
• Genetic engineering involves manipulating and isolating DNA segments using enzymes and lab techniques.
• This method can be used to combine DNA from different species or create genes with new functions.
• The resulting copies are called recombinant DNA.
• Recombinant DNA is propagated in bacteria or yeast cells whose machinery then copies the engineered DNA.
• It involves joining DNA molecules from different organisms, inserting them into a host organism for new, valuable genetic combinations.
• It is a biotechnology approach with multidisciplinary applications to address health, food resources, and environmental issues.
• Involves using enzymes and various lab techniques to manipulate and isolate DNA segments of interest.

Genetic Engineering Timeline

• From 8000 to 1000 B.C., artificial selection has been employed to manipulate organisms.
• Horses, camels, and oxen were domesticated.
• In 6000 B.C., yeast was used to make beer.
• In 5000 B.C., maize, wheat, and rice were bred.
• In 420 B.C., Socrates speculated on why children might not resemble their parents.
• In 400 B.C., Hippocrates suggested males contribute to a child's character through semen.
• From 100-300 A.D., Hindu philosophers considered reproduction and inheritance.
• By the first millennium, they established genetics foundations and observed familial diseases, believing children inherit all characteristics.
• In the 19th century, biology took a new direction with biochemical studies on nucleic acids and amino acids.
• 1864-1865: Mendel presented his work on peas in 1865, which was initially neglected, and the term gene or genetics was not yet coined
• 1882: First biotechnology products, including the use of agar described by the Koch lab.
• 1884: The autoclave was developed by a French company.
• 1895: X-rays were discovered by W. Roentgen.
• 1913: The application of X-ray crystallography by Sir William Henry Bragg.
• 1945: William Astbury coined the term molecular biology.
• Early 1950s: Rosalind Franklin and Maurice Wilkins obtained X-ray diffraction data crucial for Watson and Crick's DNA model.
• 1951: Hershey and Martha Chase showed hereditary material is DNA, not protein.
• Late 1960s: Werner Arber identified restriction enzymes in bacteria.
• 1970: Temin and Baltimore identified reverse transcriptase, leading to recombinant DNA technology.
• 1971: Paul Berg succeeded in splicing and recombining genetic material.
• 1972: The first recombinant DNA was produced in Boyer Laboratory.
• 1976: Genentech, the first biotechnology company, was established.
• 1983: Polymerase chain reaction (PCR) was invented by Karen Mullis.
• 1982: Genentech's recombinant interferon gamma and Eli Lilly's recombinant human insulin became available.
• 1986: The Human Genome Project was launched.
• 1990s: GenPharm International created the first transgenic dairy cow to produce human milk proteins; gene therapy began.
• 1997: Dolly the sheep, the first mammalian clone, was born at Scotland's Roslin Institute through somatic cell nuclear transfer.
• 1972-1974: Stanley Cohen, Herbert Boyer, and colleagues used the work of Paul Berg to develop recombinant DNA technology, spurring the biotechnology industry.

Recombinant DNA in the Lab

• Bacteria contain extra loops of DNA called "plasmids," which can be swapped.
• Investigators isolated plasmids and restriction endonucleases that cut plasmid loops by the early 1970s.
• Herbert Boyer and Stanley Cohen combined their expertise with restriction endonucleases and plasmids.
• Cohen-Boyer team cut a plasmid loop, inserted a gene, and closed the plasmid, creating recombinant DNA, and then inserted the plasmid into bacteria to create the first genetically modified organism.
• A year later, they inserted a frog gene into bacteria, meaning genes can be transferred between different organisms.
• The technology for creating “molecular chimeras” was patented on December 2, 1980.

Plasmids

• Plasmids are physically separate from chromosomal DNA and replicate independent of it.
• Plasmids typically have a few genes, notably antibiotic resistance, which can be passed from one cell to another.
• Scientists use recombinant DNA methods to splice genes into a plasmid for study.
• When a plasmid copies it also makes copies of the spliced/inserted gene.

Restriction Enzymes

• Restriction enzymes function as molecular scissors in molecular biology to cleave DNA sequences at specific sites.
• They play an important role in gene manipulation.
• Restriction enzymes recognize short DNA sequences and cleave DNA, producing cohesive (sticky) or blunt-ended fragments.

DNA Ligase

• DNA Ligase attaches two pieces of DNA

Basic Principle of Recombinant DNA technology

• Recombinant DNA is made from combining DNA from different sources in multiple steps performed in a specific sequence.
• The first step is to isolate the desired DNA in pure form, free from other macromolecules.
• Restriction enzymes play a major role in determining where the desired gene is inserted into the vector genome.
• These reactions are restriction enzyme digestions.
• Amplify a single copy of DNA into millions of copies using restriction enzymes with Polymerase Chain Reaction (PCR).
• Ligation joins a cut DNA fragment and a vector with the help of DNA ligase.
• In the insertion step, recombinant DNA is introduced into a host cell.
• This process is termed as transformation.
• Once the recombinant DNA is inserted into the host cell, it multiplies and is expressed as the manufactured protein.

Methods of Gene Transfer

• Transformation
• Vector Gene Transfer
• Transduction

Vector less Gene Transfer

• Electroporation, or electropermeabilization, allows genetic material to enter cells using pulsed electrical currents.
• It creates temporary pores in the cell membrane for the molecules to pass through and can be used on a wide array of cell types (bacteria, plant, yeast, mammalian, insect).
• Protoplast fusion fuses protoplasts derived from somatic cells belonging to different species.
• Fusion can be achieved chemically using polyethylene glycol (PEG) and calcium or physically by electrofusion.
• Microinjection introduces DNA into animal cells or plant protoplasts using a micropipette.
• This is used for creating transgenic mice.
• Microinjection involves incorporating DNA straight into the cytoplasm or nucleus.

Transduction

• Genetically engineered bacteriophages (viruses that parasitize bacteria) are introduced into a cell to create the desired recombinant DNA

Recombinant DNA Technology Applications

• Development and use of alternative fuels that burn cleaner, reducing pollution and improving air quality, can be achieved through genetic engineering.
• Micro-organisms are used to decompose wastes and clean up contaminated sites by bioremediation.
• Disease-resistant cultivars can make crop production environmentally friendly by reducing the need for agrochemicals.

Agricultural Uses

• Recombinant DNA technology can be used to modify crops to be:
  • Insect-resistant
  • Herbicide-resistant
  • Drought or freeze resistant
  • Disease resistant
  • Provided with an improved nutrition
  • Higher yield
  • Faster growth
  • Longer shelf life

Industrial Uses

• Cyanobacteria can be modified to produce plastic (polyethylene) and fuel (butanol).
• Other photosynthetic byproducts can also can be modified for industrial uses.
• E. coli bacteria have been modified to produce diesel fuel.

Health and Medicine Uses

• Treatment of genetic diseases through gene therapy, this is where the removal and replacement of defective genes with normal healthy functional genes occurs
• Examples of diseases that can be treated are Sickle cell anemia, Severe Combined Immuno-Deficiency (SCID).
• SCID is due to a defect in the gene for the enzyme adenosine deaminase (ADA) in 25% of cases.
• Production of medically useful biologicals, such as insulin.
• Vaccine production.
• Pharmacogenomics, the study of how genes affect a person's response to drugs combining pharmacology , develop effective, safe medications tailored to a person's genetic makeup.

Example Products of Genetic Engineering

• Seedless Grapes are an example of a genetically modified product.

Explore the history and development of genetic engineering, including its definition, key figures, and milestones. Discover early uses of yeast, selective breeding practices, and the advent of molecular biology. Trace the evolution of genetic engineering from ancient philosophies to modern biotechnology.