1. Biotechnology Chapter 6

2. Central Points  Recombinant DNA technology joins DNA  Biotechnology uses recombinant DNA technology to make products  Bacteria, plants, and animals modified  Safety of transgenic organisms debated  Produce human proteins for disease treatment  Many biotechnology inventions patented

3. Case A: A Taller Son for Chris  Chris’ 10-year-old son, Mike, is short  Want to treat him with human growth hormone (hGH) produced by recombinant DNA technology  If given before puberty, could help him grow  Pediatrician does not recommend hGH treatment

4. 6.1 What Is Biotechnology? VideoVideo  Coupling of genetic technology to biological systems  Makes human proteins  Previously, human proteins collected from many sources: animals, cadavers, and donated blood  Risk from these sources including death

5. In 1985, hGH Produced  Potentially unlimited amounts of growth hormone  No possibility of contamination with disease- causing agents  Used to treat a number of serious growth disorders

6. How Is hGH Produced?  Recombinant DNA technology  Transferred gene for hGH from a human cell DNA to a bacterial cell  Creating a transgenic organism  Transgenic bacterial cell and its descendants manufacture hGH

7. 6.2 Recombinant DNA Technology: Steps (1)  DNA extracted from human cells  DNA treated with restriction enzyme, cuts the DNA at specific sites, produce “sticky end”  Bacterial plasmid cut with same enzyme  Plasmid functions as vector and carries human DNA into bacterial cells

8. 6.2 Recombinant DNA Technology: Steps (2)  Fragments of human DNA and plasmid mixed together and join  Plasmids enter the bacterial cells, copy themselves, carry recombinant DNA into bacteria  Bacteria express gene, synthesize the human protein, can be used for treatments, vaccines, or other purposes

9. 2 The same restriction enzymes cut the same base sequences in plasmid DNA. 5 Recombinant DNA inserted into host cells is copied each time the host cells divide. p. 104 1 Restriction enzymes cut specific base sequences everywhere they occur in human chromosomes. 4 The result is recombinant DNA molecules with both human and plasmid DNA. 3 The plasmid DNA and the human DNA fragments are mixed in a solution with enzymes that link them together. Stepped Art Recombinant DNA Technology

10. Restriction Enzymes  Restriction enzymes cut both DNA strands at a recognition site, search for specific base sequence  > 1,000 different restriction enzymes  Each cuts at specific and different recognition sites

11. Restriction Enzymes

12. Animation: Action of restriction enzymes

13. Case A Questions  After doctor’s visit, they decide hGH not appropriate  Should parents make all medical decisions for children?  Risks of hGH use and abuse by athletes

14. Fig. 6-1, p. 106 1 The foreign gene is transferred into a plant cell. It becomes incorporated into one of the plant’s chromosomes. 2 The plant cell divides to form an embryo that develops into a mature transgenic plant as shown below. Embryo Chromosomes inside plant cell nucleus Bacterial chromosome with foreign gene inserted Stepped Art How Transgenic Plants Are Made

15. 6.3 Other Transgenic Plants and Animals  Production of medically important proteins  Transgenic crops or genetically modified (GM), plants with new characteristics Resistance to herbicides, insects, or viral or fungal diseases Increase the nutritional value of crops  Pigs for xenotransplants

16. Transgenic Crops

17. Transgenic Tobacco Produce hGH

18. Insulin from Recombinant DNA

19. Golden Rice  Genes from daffodils and bacteria  Produce beta carotene

20. Factor VIII  Clotting factor for hemophiliacs  Without the use of blood donors

21. Pigs for Possible Organ Transplant  HLA transferred to pig embryos

22. Video: ABC News: Glow-in-the-dark pigs

23. Video: ABC News: Cloned Food Approved

24. 6.4 Are Transgenic Organisms Safe?  Important to address by research and testing Health and environmental risks Economic and social issues Educate public  Potential health risks  Environmental risks, transfer of transgenes to wild plants, and reduction in biodiversity

25. 6.5 Studying Human Diseases  Human Genome Project, plant and animal genomes  Many shared genes in other species, including the mouse and Drosophila  Animal models of human disease study drug treatments and causes of disease  Transgenic organisms used for models

26. Transgenic Animal Models  Produce an animal with similar symptoms  Used to study the development and progress of a disease  Used to develop and test drugs to cure or treat animal model of the human disease Currently used for Huntington disease (HD)  Eventually, drugs used to treat humans

27. Rhino Mouse  Used to study immune deficiency conditions

28. Curly Tail Mouse  Used to study neural tube defects

29. Obese Mouse  Used to study weight-loss products

30. Case B: Strawberries on Trial  Vandals destroyed strawberries treated with transgenic “ice minus” bacteria  Why did they do this? What were the risks and benefits?  Are transgenic organisms changing the course of evolution?  See the textbook for further questions on this case

31. 6.6 Legal and Ethical Issues in Biotechnology  Patenting organisms and genes  Diamond v. Chakrabarty Oil-eating bacteria used four plasmids from different strains Produce one strain of Pseudomonas  Harvard University patent on a transgenic OncoMouse (U.S. only)

32. Issues of Patenting Transgenic Organisms

33. Spotlight on Ethics: Asilomar Conference, 1975  Potential hazards presented by recombinant DNA technology  Guidelines 1.Organisms be contained 2.Level of containment should match risk 3.Physical barriers should be used 4.Prohibited experiments risk too high  Video Video