Genetic Engineering

• Genetic engineering is the process of using recombinant DNA (rDNA) technology to alter the genetic makeup of an organism
• Genetic engineering is also known as genetic modification or genetic manipulation
• Since ancient times, genetic engineering practices have begun
• Artificial selection is done to indirectly manipulate genes focusing on physical traits among organisms
• Selective breeding is when animals with desired characteristics are mated to produce offspring with those desired traits
• Hybridizations are when two individuals with unlike characteristics are crossed to produce the best in both organisms
• Inbreeding is a technique of breeding genetically similar organisms to maintain desired traits
• Recombinant DNA Technology involves mixing DNA from two different sources
• Restriction enzymes are used to splice, connect, and remove or add nucleotides to DNA sequences
• Inserting the desired gene into the genome of the host involves selecting the gene and a vector (plasmid or bacteriophage) to form recombinant DNA
• The three modes of gene transfer between bacteria are transduction, transformation, and conjugation
• Golden rice is genetically modified to produce beta carotene, which is converted into Vitamin A in the human body
• DNA technology is used to engineer genes of cultured cells for practical purposes
• Bacteria can transfer genetic material through transduction, transformation, and conjugation
• Genetic engineering has been used to produce insulin from yeast and bacteria like E. coli
• Transduction is the process by which a virus transfers its genetic material to a host cell
• Conjugation is the process by which one bacterium transfer genetic material to another through direct contact.
• The ability of ubacterial cell to carry out conjugation is usually due to a specific piece of DNA called plasmid.
• Plasmid is a circular DNA molecule smaller than and separate form the bacterial chromosome
• Plasmid is the main tool for DNA technology
• The genetic engineering process

  1. plasmid is extracted from bacteria or yeast cell
  2. a small section is then cut by restriction enzyme
  3. gene from human insulin is inserted into the gap
  4. glued by dna ligase
  5. genetically modified plasmid is introduced as a new bacteria or yeast cell
  6. fermentation
  7. purification
  8. insulin is ready for distribution
• in 1973 the first genetically modified bacteria is created
• in 1974 the first GM mice is created
• in 1982 the first commercial development of GMOs
• in 1994 it began to sell genetically modified food
• in 2003 it began to sell GMOs as pets
• Bacteria are the most common GMOs because their simple structure permits easy manipulation of their DNA
• Cyanobacteria have been modified to produce plastic and fuel
• E. coli bacteria have been modified to produce diesel fuel
• Banana Vaccines

  Modified virus injected in sapling tree causes the bananas to contain virus proteins
• Venomous Cabbage

  Scorpion genes added to the cabbage prevent insects from eating it
• Fast-Growing Salmon

  Genes from two other fish cause this salmon to continually produce growth hormones
• Less Smelly Cows

  Modifying bacteria responsible for methane production in cattle results in 25% less-flatulent cows
• Genetic engineering is the direct modification of an organism's genome, which is the list of specific traits (genes) stored in the DNA
• Changing the genome enables engineers to give desirable properties to different organisms
• Organisms created by genetic engineering are called genetically modified organisms (GMOs)
• The GMO process affects the protein synthesis of the organism

  • By changing which proteins are produced, genetic engineers can affect the overall traits of the organism
  • Genetic modification can be completed by a number of different methods:
  • Inserting new genetic material randomly or in targeted locations
  • Direct replacement of genes (recombination)
  • Removal of genes
  • Mutation of existing genes
• GMO Bacteria:

  • Bacteria are the most common GMOs because their simple structure permits easy manipulation of their DNA
  • One interesting use for genetically modified bacteria is the production of hydrocarbons (plastics and fuels)
  • Cyanobacteria have been modified to produce plastic (polyethylene) and fuel (butanol) as byproducts of photosynthesis
  • E. Coli bacteria have been modified to produce diesel fuel
• Genetically Modified Crops:

  • GMO crop production in the US (2010): 93% of soybeans, 93% of cotton, 86% of corn, 95% of sugar beets
  • Example: One common modified crop is Bt-corn, where a gene from the Bt bacteria is added so the corn produces a protein that is poisonous to certain insects but not humans
• Other Reasons to Genetically Modify Crops:

  • Insect resistant
  • Herbicide resistant
  • Drought/freeze resistant
  • Disease resistant
  • Higher yield
  • Faster growth
  • Improved nutrition
  • Longer shelf life