V. GENETIC TECHNOLOGY Genetically Modified Organisms Transgenic Organism: a genetic change in each of its cells, after the addition of a gene from a different species Transgenic pig with gene from E.coli – manure with 75% less phosphorus than normal pig excrement Biotechnology: use or alteration or biological molecules for specific applications Genetic Engineering/Genetic Modification: refer broadly to any biotechnology that manipulates genetic material Recombinant DNA Technology: 1st of the modern biotechnologies; adds genes from 1 type organism to another

Constructing Recombinant DNA Molecules Restriction enzymes cut donor and recipient DNA DNA to carry the donor DNA (cloning vectors) Recipient cells (bacteria)

Cloning Vector: carries DNA from the cells of 1 species into the cells of another Plasmid: a small circle of double-stranded DNA; occurs naturally in bacteria, yeasts, plant cells Bacteriophages: viruses that infect bacteria Genomic Library: a collection of recombinant bacteria that contains pieces of a genome

Inserting DNA into Animal Cells Chemicals: Polyethylene glycol and calcium phosphate used to open holes in cell membranes, admitting DNA Liposomes: fatty bubbles that carry DNA into cell as cell membrane envelopes them Electroporation: brief jolt of electricity opens holes in cell membrane Microinjection: DNA injected into cells using microscopic needles Particle Bombardment: Gunlike device shoots metal particles (gold, tungsten) coated with foreign DNA at cell membrane

Applications of DNA Technology Mass produce protein-based drugs (insulin) Textiles: creation of a new source of indigo (using E. coli) Paper and Wood Products: technology to prevent trees from insect attack Food: added nutritional value; extended shelf life; improved flavor Bioremediation: Plants or bacteria with the ability to detoxify certain pollutants are released or grown in a particular area to clean the environment 1989 Oil Spill in Alaska’s Prince William Sound (Nitrogen and phosphorus fertilizer distributed along shore caused increase in native population of bacteria that consumed organic toxins in the oil)

Gene Targeting More precise method of genetic modification Uses homologous recombination: DNA sequence displaces a similar or identical sequence in a host chromosome Done on ES (embryonic stem) cells

Antisense Technology Selectively blocks expression of genes Inserts a DNA sequence in reverse orientation Limitations: must be given intravenously; do not enter cells; unpredictable results Drug used to treat eye infections (AIDS) Clinical Trials: Drugs for diabetes, Crohn Disease, psoriasis, rheumatoid arthritis