Genetically Modified Organisms

1. Genetically Modified Organisms Chapter 15 (ibook)

2. GMO: Genetically Modified Organism • GMO: organism whose genome has been engineered in the laboratory in order to favour the expression of desired physiological traits or the production of desired biological products. • NY Times – Genetically Modified Food Navigator • Britannica article • Britannica GMO background

3. More New Vocab • Biotechnology – process of manipulating organisms, cells, or molecules to produce a specific products. • Recombinant DNA - DNA produced by combining DNA from different sources. • Transgenic organism– containing genes from another species • host that carries the inserted DNA from one or more organisms = genetically modified organism

4. Genetic Engineering/Modification • Selective Breeding (hybridization vs. inbreeding) • Ex: dog breeds • 1849 -1926 Luther Burbank (botanist) developed more than 800 varieties of plants via hybridization Hybridization – crossing dissimilar individuals to bring together the best of both. Inbreeding– maintains desirable characteristics in a line of organisms • Associated risk: increase chance that a cross will bring together 2 recessive alleles for genetic defect.

5. Crop Desired trait (color) Cross breeding Pear Apple Offspring Cross breeding Best results New offspring Desired result Fig. 12.11, p. 273

6. Biotech Crops in the United States [from Wikipedia] Fig. 9-10 here

7. The Objectives of Genomics • Disease resistance • Drought tolerance • Frost tolerance • Salt tolerance • Improved nutritional value • Incorporate human vaccines

9. The Problems with Genomics • Environmental concerns • Not considered safe by all consumers • Not affordable in all countries • Major player in the future of agriculture • Might keep food production in pace with population growth

10. Environmental Problems • Pest resistance to genetically engineered toxin • Broad spectrum impact on non-target species • “Super weeds” • Contamination (decreasing natural variation)

11. Food Safety Issues • Proteins cause allergic responses • Antibiotic resistance to human pathogens • Plant produces new toxic substances

12. Summary: GMF Controversy • Unexpected plant mutations create higher toxin levels • Introduce new allergens into foods • Lower nutritional value • Don’t help feed world’s hungry • Reduce effectiveness of natural pesticides • Resistant genes passed on through pollination to wild relatives = super weeds • Increased herbicide use on resistant crops • Increased costs of food to cover devp. & patenting of GMF • Rapid evolution of pesticide resistant insects. • Killing beneficial insects – monarch butterfly • Introducing chemicals into soil killing soil organisms • Irreversible and unpredictable genetic & ecological effects

13. Polymerase Chain Reaction • Amplifies a selected section of DNA quickly • Provides LOTS of DNA to work with and analyze • PCR animation • PCR tutorial • PCR song

14. 35S Promoter Gene • This is a “marker” found in many GMO’s • from cauliflower mosaic virus; allows modified genes to enter original modified plant cells • Wild Type : no marker = (-) • Round-Up Ready: yes marker = (+) • Your food sample: • (-) result = not a GMO • (+) result = yes a GMO!

15. Tubulin Protein • Plant protein found in all plants, therefore, the gene for this protein should be found in all plant DNA samples. • (-) Your sample is missing plant DNA! • (+) Your sample contains captured plant DNA!

16. Results you should get: • Wild Type Soy Bean: (-) 35s (+) Tubulin • Round-Up Ready Soy Bean: (+) 35 s (+) Tubulin • Your Food Item: (???) 35s (+) Tubulin unless your food is really over-processed!

17. Gel Electrophoresis • Physically separate different sized fragments through an agarose gel using an electrical current • Tutorial 1 • Tutorial 2 - Work through 4 Discovery Modules • Tutorial 3- Go to “Manipulation” then “techniques” then “sorting and sequencing”