Genetic engineering

• Genetic engineering


  Process of using biotechnology to alter the genes / DNA of an organism
• Genetic engineering


  • Used to add a desirable trait or remove an undesirable trait or correct a disorder / mutation
  • Done by altering a gene sequence (change bases) or adding a gene or removing a gene
  • Modified genes then copied to all daughter cells when parent cell divides by mitosis
  • If modify gene in gametes (sex cells) then it will be passed down to offspring as well
• Genetically Modified Organism (GMO)


  Any organism that has had it own DNA artificially modified to produce a desired characteristic
• Transgenic Organism (TGO)


  An organism that contains DNA from an unrelated species
• All transgenic organisms are GMOs


  But not all GMOs are transgenic
• Canola


  • Modified to carry 2 genes from bacteria that makes the plant resistant to a common herbicide
• Golden Rice-2


  • Rice genetically modified using genes from daffodils, corn and bacteria
  • Contains beta-carotene for Vitamin A
• Some community groups are concerned about effects of GMOs on humans and other organisms
• Restriction enzyme


  Cut sugar-phosphate backbone of double-stranded DNA at a specific recognition site made up of a specific DNA sequence
• DNA ligase


  Enzyme used to join sugar-phosphate backbone of different pieces of DNA
• DNA polymerase


  Enzyme used to synthesise chains of DNA from nucleotides
• CRISPR-Cas9


  • System used by bacteria to protect themselves from attacks from viruses
  • Can be used in genetic engineering to scan specific sequences of DNA to alter / delete / add DNA bases
• CRISPR-Cas9


  1. CRISPR scans for a specific sequence of DNA

  2. Scientists can create a synthetic guide nucleotide sequence for CRISPR to use to scan DNA

  3. Cas9 enzyme cuts the selected sequence of DNA

  4. Scientists can then inject particular nucleotide sequences into cell to insert into the gap
• Recombinant DNA technology


  Technology that allows DNA from different sources to be recombined with other genes
• Vectors


  A vehicle / method for transporting genetic material
• Plasmids


  Rings of DNA found in bacteria, used as vectors to insert gene of interest for medical treatment or make a protein (e.g. Insulin) or to make genetically modified organisms
• Recombinant plasmids


  Plasmids that has a gene from another species inserted into it
• Bacterial transformation


  Process by which bacteria take up foreign DNA by taking up the recombinant plasmid
• Plasmids


  • Small which makes them easier to manipulate
  • Contain a variety of recognition sites for restriction enzymes, so scientists can mix and match restriction enzymes to produce the most suitable cut
  • Capable of self-replication which means that they can make lots of copies of themselves
• Bacteria


  • Can multiply rapidly (on average every 20 minutes)
  • Rapid multiplication of plasmids and bacteria ideal for mass production of a protein (E.g. Insulin)
• Recombinant DNA technology: Bacterial Transformation

  1. Plasmids are removed from a bacterium

  2. Plasmid is cut using a restriction enzyme

  3. Gene of interest (e.g. Insulin gene) is removed from a human cell

  4. Same restriction enzyme is used to cut gene out

  5. Human gene is inserted into plasmid using Ligase enzyme to form recombinant plasmid

  6. Recombinant plasmid is put into a bacterium via process of bacterial transformation

  7. Bacterial cells multiply rapidly and make multiple copies of gene and produce protein of interest
• Uses of Bacterial Transformation

  • Insulin to manage diabetes
  • Erythropoietin to treat anaemia
  • Chymosin for cheese production
  • Growth hormone to manage growth disorders
  • Interferon to treat some cancers