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? Video • 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. 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. 2 The same restriction enzymes cut the same base sequences in plasmid DNA. 3 The plasmid DNA and the human DNA fragments are mixed in a solution with enzymes that link them together. 5 Recombinant DNA inserted into host cells is copied each time the host cells divide. Recombinant DNA Technology Stepped Art p. 104

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

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 diseasestudy 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 • Organisms be contained • Level of containment should match risk • Physical barriers should be used • Prohibited experiments risk too high • Video