genetic engineering + evolution

• Genetic engineering


  The artificial alteration or manipulation of genes
• Steps in genetic engineering (ICT IE)


  1. Isolation

  2. Cutting

  3. Transformation

  4. Introduction of base sequence changes

  5. Expression
• Isolation


  DNA containing the target gene is removed from the organism, and the plasmid is removed from the bacterium
• Cutting


  The DNA removed from the target organism is cut into many fragments using restriction enzymes
• Transformation


  The target gene is inserted into the plasmid DNA using DNA ligase
• Introduction of base sequence changes

  The recombinant DNA (plasmid with inserted gene) is introduced into a bacterium
• Expression


  The successfully transformed bacteria multiply, producing many identical clones that express the inserted gene and form the desired product
• Bacterial plasmids are commonly used as vectors in genetic engineering
• Restriction enzymes act like scissors, recognizing and cutting DNA at specific sequences of nucleotides
• Bacteria use restriction enzymes to fight against bacterial viruses (phages)
• DNA ligase is an enzyme that reconnects the plasmid after the target gene is inserted
• Recombinant DNA refers to the DNA of the plasmid and the inserted gene becoming one unit
• Bacterial cells are made more permeable to accept the recombinant plasmid by suspending them in a medium containing calcium ions
• Plasmids used as vectors in genetic engineering often contain a gene for antibiotic resistance, allowing selection of transformed bacteria
• Probes are used to identify bacteria that contain the plasmid with the inserted gene (recombinant DNA)
• Applications of genetic engineering


  • Herbicide resistant crops
  • Inserting genes into sheep to treat emphysema
  • Production of insulin by bacteria
• Bacteria communicate using quorum sensing, as discovered by scientist Bonnie Bassler
• Genetic engineering


  The artificial manipulation or alteration of genes
• Genetic engineering


  • Taking genes from one organism and placing them into another, can be same or different species
• Genetic engineering


  • There has to be some benefit, e.g. creating herbicide resistant crops
• Genetically engineering a microorganism to produce a useful product


  1. Isolate gene for insulin production from human cell

  2. Insert into bacterium

  3. Bacterium produces many identical clones with insulin production gene

  4. Insulin produced in bioreactors
• Genetic engineering using animals

  • Inserting gene for AAT protein into sheep
  • Sheep are transgenic and express AAT protein in milk
  • Protein purified from milk and used to treat conditions like emphysema
• Steps in genetic engineering

  1. Isolation

  2. Cutting

  3. Transformation

  4. Introduction of base sequence change

  5. Expression
• Isolating DNA for genetic engineering


  1. Remove DNA with specific gene of interest from organism

  2. Remove bacterial plasmid, which will act as vector
• Cutting DNA for genetic engineering


  1. Use restriction enzyme to cut DNA with gene of interest into fragments

  2. Also cut bacterial plasmid with same restriction enzyme
• Transformation in genetic engineering


  1. Insert target gene into bacterial plasmid using DNA ligase enzyme

  2. Recombinant DNA inserted into bacterium
• Introduction of base sequence change in genetic engineering

  New gene is now inside the organism
• Expression in genetic engineering

  1. Transformed organism reproduces, producing many identical clones

  2. Inserted gene is expressed, producing the desired protein product
• Evolution


  The way in which living organisms changed genetically to produce new forms of life over long periods of time
• Charles Darwin and Alfred Russel Wallace


  • Worked independently and came up with the same theories of evolution
• Darwin's theory of evolution (natural selection)


  Published in 'The Origin of Species'
• Genetic variation


  Differences in the A's, T's, C's and G's of the DNA that makes each individual unique
• Genetic variation is the key driver of evolution
• Causes of genetic variation


  • Sexual reproduction
  • Chromosomal mutations
  • Gene mutations
• Chromosomal mutations


  Changes to the structure and number of chromosomes
• Gene mutations


  Changes in the structure or amount of DNA, including deleting, inserting or changing DNA bases
• Causes of genetic mutations include exposure to mutagenic agents like chemicals, radiation, and hazardous substances
• Speciation


  The process by which new species form, often due to geographic or reproductive isolation leading to genetic changes over time
• Natural selection


  The process by which beneficial genetic variations are selected for, enabling those organisms to survive, thrive and pass on those traits
• Examples of beneficial traits selected for by natural selection

  • Echolocation
  • Resistance to infection
  • Speed to escape predators
  • Excellent eyesight
  • Camouflage