genetic engineering

• Bacteria given a gene from a bioluminescent jellyfish

  • Bacteria gained ability to glow under UV light
• Bacteria can be given a human gene
• Insulin


  Hormone made by the pancreas that helps cells get the glucose they need
• Type 1 Diabetes


  Condition where the pancreas doesn't make enough insulin, so the individual must take insulin injections
• Producing insulin in a lab using bacteria

  1. Bacteria given the human gene for insulin

  2. Bacteria produce the insulin

  3. Insulin is purified and used for humans
• Transformation


  Process where a cell, commonly bacteria, can take up DNA from their environment and use that DNA
• Genetic engineering


  Changing an organism's genotype using biotechnology tools or techniques
• Human cell


  • Contains a nucleus with the organism's entire DNA code
  • Most body cells contain all of your DNA
• Plasmid


  An extra set of genes, in addition to the bacterial chromosome, that bacteria can use
• Inserting a human gene into a bacterial plasmid

  1. Use restriction enzymes to cut the plasmid

  2. Use ligase to seal the human gene into the plasmid

  3. Resulting DNA is recombinant DNA
• Transgenic


  Any organism or microorganism that has genetic material from some other organism
• Vector


  The vehicle for getting recombinant DNA into an organism, e.g. plasmids or viruses
• Genetic engineering techniques


  • Microinjection
  • Gene guns
• CRISPR


  Gene editing tool that uses a Cas9 nuclease and guide RNA to cut DNA at specific target sites
• Uses of genetic engineering

  • Medical applications (insulin, clotting factors, human growth hormone)
  • Agricultural applications (pest/herbicide resistant crops, plants that remove pollutants)
  • Research applications (genetically engineered mice)
• There are ethical considerations for genetic engineering that must be examined and considered
• The career of a genetic engineer is expected to keep growing
• Genetic engineering


  The set of technologies used to alter the genetic makeup of cells. It includes transfer of genes within and across the species to produce novel organisms.
• Genetic engineering has numerous applications in research, agriculture, industrial biotechnology and medicine
• Recombinant DNA


  A DNA molecule produced by combining DNA from different sources
• Steps in producing recombinant DNA

  1. Cut out a piece of DNA from a DNA molecule

  2. Insert piece of DNA from organism into the DNA of another organism

  3. Use a restriction enzyme to cut DNA from sticky ends

  4. Read the sequence of bases in a piece of DNA in case of mutation

  
• Restriction enzyme


  DNA-cutting enzymes that recognize one or a few target sequences and cut DNA at or near those sequences

  
• EcoRI


  A common restriction enzyme that cuts DNA at the sequence G/AATTC, leaving 5 nucleotide sticky ends with 5' end overhangs of AATTC

  
• General steps of recombinant DNA technology

  1. Isolating of DNA

  2. Cutting or cleavage of DNA by restriction enzymes

  3. Selection of an appropriate vector

  4. Ligation of the gene of interest with the vector

  5. Amplifying the recombinant DNA

  6. Selection process to screen which cells contain the gene of interest

  7. Sequencing of the gene to find out the primary structure of the protein

  
• Plasmid


  A small, circular, double-stranded DNA molecule that is distinct from a cell's chromosomal DNA and naturally exists in bacterial cells

  
• Ways to introduce plasmids to host organisms

  1. Biolistics (using a "gene gun" to fire DNA-coated pellets)

  2. Plasmid insertion by Heat Shock Treatment

  3. Electroporation (using an electric "shock" to expand membrane pores)
• Methods to screen recombinant cells

  1. Selection of plasmid DNA containing cells (using antibiotic resistance genes)

  2. Selection of transformed cells with the desired gene (using visible markers like chromogenic or fluorescent proteins)
• Transformation of cells


  Allow plasmid-containing cells to grow and propagate into colonies
• Selection of transformed cells with the desired gene

  1. Antibiotic resistance genes allow for selection of transformed cells

  2. Inserted genes produce colored or fluorescent products that label the colonies/cells
• Blue-white screening


  1. Insertion of gene in cloning site disrupts β-galactosidase gene

  2. Cells transformed with disrupted gene remain "white" in presence of IPTG

  3. Allows screening for cells transformed with desired gene

  
• PCR detection of plasmid DNA

  1. PCR amplification confirms presence of desired gene

  2. PCR reactions identify type of plasmid used for transformation

  
• Genetically Modified Organisms (GMOs)

  • Ability to insert gene sequences provides new traits
  • Some GMOs promise higher product yield
• Flavr-Savr Tomato and Bt-Corn are examples of GMOs
• Concerns regarding consumption of GMO foods

  • Possibility of undetectable hazards
  • Manufacturers urged to provide labels notifying consumers of GMO presence

  
• GMOs are believed to be safe when licensed by food regulatory agencies
• Consumers must be provided with enough information to make their own choices regarding use of GMOs
• Genetic engineering


  The process of manually adding new DNA to an organism to add one or more new traits that are not already found in that organism
• Genetically engineered (transgenic) organisms currently on the market

  • Plants with resistance to some insects
  • Plants that can tolerate herbicides
  • Crops with modified oil content
• DNA


  The recipe for life, a molecule found in the nucleus of every cell and made up of 4 subunits (A, T, G, C) that hold a code of information for the cell
• Gene


  A small segment of DNA that holds the instructions for how to produce a single protein