Biotechnology Chapter 6

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

6.1 What Is Biotechnology? 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

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

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

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

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

Recombinant DNA Technology

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

Restriction Enzymes

Animation: Action of restriction enzymes

How Transgenic Plants Are Made

Animation: Studying and Manipulating Genomes (formation of recombinant DNA)

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

Transgenic Crops

Transgenic Tobacco Produce hGH

Insulin from Recombinant DNA

Golden Rice Genes from daffodils and bacteria Produce beta carotene

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

Pigs for Possible Organ Transplant HLA transferred to pig embryos

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

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

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

Rhino Mouse Used to study immune deficiency conditions

Curly Tail Mouse Used to study neural tube defects

Obese Mouse Used to study weight-loss products

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)