Genetic Modification

Early Forms of Genetic Manipulation

• Selection: choosing organisms with favored traits and allowing them to reproduce.
• Hybridization: breeding dissimilar organisms to produce hybrids.
• Inbreeding: breeding similar or related organisms.
• Mutation breeding: subjecting plant seeds to UV rays and growing the seeds.

Modern Techniques in Genetic Modification

• Recombinant DNA
• Genetically modifying plants
    * Gene gun
    * Micropropagation
• Xenotransplantation

Recombinant DNA

• Restriction Enzymes: enzymes that cut DNA at particular sequences.
• DNA Ligase Enzyme: enzymes that join the cut ends of DNA molecules.
• Plasmids: small circles of DNA found in bacteria

Inserting Foreign Genes

1. Isolate a gene and cut it out with a restriction enzyme.
2. Cut plasmids with the same restriction enzyme.
3. Allow “sticky ends” to join.

• Bacteriophage: viruses that infect bacteria
    * Can be used to insert foreign genes into bacteria

Applications of Genetic Engineering

• Transgenic Bacteria: engineered biomolecules like insulin and other pharmaceutics can be harvested from them.
• Transgenic Plants: crops are genetically engineered for higher yield, pesticide resistance, and producing their own fertilizer.
• Transgenic Animals: used for farming, ranching, or genetic research.

Transgenic Bacteria

• Involves fusion of foreign DNA fragments with bacteria to manufacture:
    * Human insulin
    * Enzymes for washing powders
    * Enzymes in the food industry
    * Human growth hormone
    * Bovine Somatotropin (BST)
    * Human vaccines

Transgenic Plants

• Involves the insertion of foreign DNA into plants for the following reasons:
    * Higher yield
    * Pesticide resistance
    * Producing own fertilizer
    * Heat and drought tolerance
    * Salt tolerance
    * Better nutrient balance
• Involves the insertion of foreign DNA into plants using the following:
    * Agrobacterium - soil bacteria that regularly insert plasmids into plant cells.
    * Gene Gun - fires a gene-coated gold pellet into plant cells.

Transformation

• Involves fusion of foreign DNA fragments with “plasmids” of Agrobacterium.
    * Plasmid leaves bacteria and invades plant cells, inserting itself into its DNA.

Moral, Ethical, and Social Concerns

• Moral concerns - “playing God” and the unforeseen consequences of these alterations.
• Ethical concerns - contamination of “wild” plants and animals, development of superweeds.
• Social concerns - genetically engineered seeds may not be available except for those who can afford them.