Introduction to Genetic Engineering

Genetic Engineering Definition

• Genetically engineered organisms have had their DNA altered by humans
• Genetic engineering is the process of altering an organism’s DNA
• Ethical considerations surround genetic engineering as humans are altering the fundamental building blocks of life
• Practical applications exist for genetic engineering across medicine, agriculture, and commercial markets

Genetic Engineering History

• Selective breeding, dating back thousands of years, is an early form of genetic engineering
• Modern genetic engineering started in 1973 with scientists Herbert Boyer and Stanley Cohen, who first successfully cut and pasted DNA into bacteria
• The Supreme Court ruling allowing patenting of genetically engineered organisms in 1982 facilitated further research and applications

Genetic Engineering Process

• Genetic engineering involves processes of isolating, cloning, and inserting genes into a host organism’s genome
• Host: The organism receiving the modified DNA
• Vector: The method used to transfer recombinant DNA into a host, which can be made of DNA or composed of a living system (e.g., bacteria or virus)
• Plasmid: A circular piece of DNA used as a vector to transfer small pieces of recombinant DNA into bacteria
• Restriction enzymes: Cut both the isolated gene and the vector at specific sequences, creating complementary ‘sticky ends’
• DNA ligase: An enzyme that joins the isolated gene and vector together, creating a recombinant DNA molecule

Transgenic Organisms vs. Genetically Modified Organisms

• Transgenic organisms: Have DNA from a different species incorporated into their genome
• Genetically modified organism (GMOs): Organisms with altered DNA, but not necessarily containing DNA from a different species
• All transgenic organisms are GMOs, but not all GMOs are transgenic

Genetic Engineering Examples

Agriculture

• Bt cotton:
  • Contains genes from Bacillus thuringiensis bacteria
  • These genes produce an insecticide that helps protect the cotton from insects, leading to increased crop yield
• Golden rice:
  • Contains genes for plant phytoene synthase (psy) and a bacterial phytoene desaturase
  • These genes produce beta-carotene, a key precursor to vitamin A, in the rice grains
  • Aims to address vitamin A deficiencies, particularly in developing nations

Medicine

• Human insulin production in bacteria:
  • Bacteria are genetically engineered with the human gene for insulin, enabling mass production of the hormone
  • Enables treatment of diabetes

Research

• Knock-in and knock-out organisms:
  • Used to study gene function by adding or removing genes from the genome
  • Help understand the effects of specific genes and their roles in development and disease
• Disease models:
  • Created to understand human disease by modifying genes in cells or organisms
  • Allow scientists to study disease progression, investigate potential treatments, and identify drug targets

Commercial Uses

• Glow organisms:
  • Organisms engineered to express the green fluorescent protein (GFP) from jellyfish
  • Used for research and commercial purposes
  • Examples include rabbits, cats, and fish