Genetic Engr

• Classical Breeding:

  • Seeds for seedless melons are produced by crossing a normal watermelon with one genetically modified by treatment with colchicine
  • Crossed seeds produce plants that, when pollinated with pollen from normal plants, produce seedless melons
  • Focuses on mating organisms with desirable qualities
  • Examples include controlled pollination of plants and mating of animals with desired traits
• Genetic Engineering:

  • Direct manipulation of genes for practical purposes
  • Applications include manufacturing useful products
  • Scientists can make recombinant DNA in vitro using biochemical and mechanical tools
  • Modification of traits may involve introducing new traits, enhancing present traits by increasing expression of desired gene, or disrupting inhibition of desired genes' expression
• Recombinant DNA Technology:

  • Involves ligation of gene of interest with vector, selection of appropriate vector, cutting of DNA by restriction enzymes, sequencing of gene, selection process to screen cells containing gene, and transfer of recombinant plasmid into host cell
  • Molecular biology techniques are used for insertion and expression of proteins in different organisms
• Plasmids:

  • Small circular double-stranded DNA molecules found in bacteria and some other microscopic organisms
  • Carry few genes and exist independently of chromosomes
  • Able to self-replicate and transfer between bacteria
  • Used by host organisms to cope with stress-related conditions
• Three Ways Plasmids May Be Introduced Into Host Organisms:

  1. BIOLISTICS: Gene gun technique used to fire DNA-coated pellets on plant tissues

  2. HEAT SHOCK TREATMENT: Process to transfer plasmid DNA into bacteria by increasing pore sizes of plasma membranes

  3. ELECTROPORATION: Expansion of membrane pores through an electric shock, commonly used for insertion of genes into mammalian cells
• Genetically Modified Organisms (GMOs):

  • Flavr-Savr Tomato: Modified ripening process to delay softening of fruit
  • Bt-Corn: Production of Bt-endotoxin from Bacillus thuringiensis to kill pests
  • Cloning: Creating genetically identical organisms through asexual reproduction
  • Dolly: First mammal cloned, had the same DNA as her mother and no father
• Classical Breeding:

  • Seeds for seedless melons are produced by crossing a normal watermelon with one genetically modified by treatment with colchicine
  • Crossed seeds produce plants that, when pollinated with pollen from normal plants, produce seedless melons
  • Focuses on mating organisms with desirable qualities
  • Examples include controlled pollination of plants and mating of animals with desired traits
• Genetic Engineering:

  • Involves direct manipulation of genes for practical purposes
  • Applications include manufacturing useful products
  • Scientists can make recombinant DNA in vitro using biochemical and mechanical tools of DNA technology
  • Modification of traits may involve introducing new traits, enhancing present traits by increasing expression of desired gene, or disrupting inhibition of desired genes' expression
• Recombinant DNA Technology:

  • Involves ligation of gene of interest with vector (e.g., from animal with cut bacterial plasmid)
  • Selection of appropriate vector to propagate recombinant DNA
  • Cutting or cleavage of DNA by restriction enzymes
  • Sequencing of gene to find primary structure of protein
  • Transfer of recombinant plasmid into host cell for replication
• Plasmids:

  • Small circular double-stranded DNA molecules found in bacteria and some other microscopic organisms
  • Carry few genes and exist independently of chromosomes
  • Able to self-replicate and transfer between bacteria
  • Used by host organisms to cope with stress-related conditions
• Biolistics:

  • "Gene gun" technique used to fire DNA-coated pellets on plant tissues
  • Cells that survive bombardment and take up expression plasmid coated pellets acquire ability to express designed protein
• Heat Shock Treatment:

  • Process used to transfer plasmid DNA into bacteria
  • Cells pre-treated to increase pore sizes of plasma membranes
  • Cells made competent for accepting plasmid DNA
  • Plasmids concentrate near cells during treatment
  • Rapid temperature changes increase and decrease pore sizes in membrane, allowing plasmid DNA uptake
  • Transformed cells acquire new traits
• Electroporation:

  • Technique involving expansion of membrane pores through electric "shock"
  • Commonly used for insertion of genes into mammalian cells
• Genetically Modified Organisms (GMOs):

  • Flavr-Savr Tomato: modified ripening process to delay softening of fruit
  • Bt-Corn: incorporates production of Bt-endotoxin from Bacillus thuringensis to kill pests
  • Cloning: creating genetically identical organisms through asexual reproduction
• Classical breeding involves crossing a normal watermelon with one genetically modified by treatment with colchicine to produce seedless melons
• Genetic engineering is the direct manipulation of genes for practical purposes
• Applications of genetic engineering include the manufacture of various useful products
• Scientists can make recombinant DNA in vitro using biochemical and mechanical tools of DNA technology
• Traits modification in genetic engineering may involve:

  • Introduction of new traits into an organism
  • Enhancement of a present trait by increasing the expression of the desired gene
  • Enhancement of a present trait by disrupting the inhibition of the desired genes’ expression
• Plasmids are small circular double-stranded DNA molecules found in bacteria and some other microscopic organisms
• Plasmids can self-replicate and be transferred between bacteria to cope with stress-related conditions
• Three ways to introduce plasmids into host organisms:

  • Gene gun technique (biolistics)
  • Heat shock treatment
  • Electroporation
• Heat shock treatment involves transferring plasmid DNA into bacteria by increasing pore sizes of plasma membranes through temperature changes
• Electroporation is a technique that uses an electric "shock" to expand membrane pores for gene insertion, commonly used for mammalian cells
• The first genetically modified organism licensed for human consumption was the Flavr-Savr ("Flavor Savor") Tomato, modified to delay fruit softening
• Bt-Corn was developed to produce a toxin from Bacillus thuringensis that kills pests like corn borer larvae but is non-toxic to humans and animals
• Cloning involves creating an organism that is an exact genetic copy of another, like Dolly the sheep, the first mammal cloned
• Identical twins are naturally created clones with the same DNA as the parent
• Cloning is a form of asexual reproduction with only one genetic parent
• The process of cloning involves growing an entire individual from a single cell removed from a parent organism
• Each cell in the body has the same DNA, but different genes are turned on in each cell
• Dolly had the same DNA as her mother and no father, showcasing cloning as a form of asexual reproduction