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Chapter 13

Chapter 13 . Gene Technology. Facts about Human DNA. Except for identical twins, no one has the same DNA 10% of genome is different (person to person) Use these differences to compare/ID Restriction length polymorphisms (RLPM) (Variable number tandem repeat). DNA fingerprinting.

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Chapter 13

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  1. Chapter 13 Gene Technology

  2. Facts about Human DNA • Except for identical twins, no one has the same DNA • 10% of genome is different (person to person) • Use these differences to compare/ID • Restriction length polymorphisms (RLPM) • (Variable number tandem repeat)

  3. DNA fingerprinting • Able to compare DNA samples in regions of a chromosome that differs • Use in • paternity • identification of human remains • tracing human origins • evidence in criminal cases

  4. Steps in Identification • Copy DNA (Polymerase Chain Reaction) • Cutting DNA (Restriction Enzymes) • Sorting DNA by size (Electrophoresis)

  5. Polymerase Chain Reaction (PCR) Don’t have enough of a sample-need to make copies

  6. Cutting DNA: Restriction Enzymes EcoR1: Bacterial protein

  7. Sort DNA: Gel Electrophoresis • Cut DNA is placed in wells of thick gel • Electric current runs through gel • Negatively charged DNA migrate to + end • Smaller fragments go faster and farther

  8. Cloning • Introduction of a nucleus from a body cell into an egg cell to generate an organism identical to the nucleus donor • Dolly(1996) • Suffered premature aging and disease • Had short telomeres-premature aging • Died at age 6 • Other cloned species, have not had telomere shortening • http://images.google.com/imgres?imgurl=http://wwwimage.cbsnews.com/images/2004/09/08/image642074x.jpg&imgrefurl=http://www.cbsnews.com/stories/2004/09/08/eveningnews/main641999.shtml&usg=__3XK03j8Ov6p2Nh2zP2HJh70LFtI=&h=278&w=370&sz=15&hl=en&start=12&um=1&tbnid=ReSiW4_1Z6oO4M:&tbnh=92&tbnw=122&prev=/images%3Fq%3Dclone%2Byour%2Bpet%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN

  9. GENE THERAPY • Use of nucleic acids as medicine • Introduction of a gene into a patient’s cell • 5,000+ people worldwide are already treated with Gene Therapy

  10. How does it work? • Isolate the functional gene • Insert the healthy gene into a viral vector • Introduce the recombinant virus to the patient (infect the patient)

  11. Cystic Fibrosis • Lung disease • Lack of functional gene (CFTR gene) • Encodes for a protein that helps transport ions into and out of cells in breathing passage • Without the gene: poor ion exchange causes the buildup of sticky mucus that blocks the airway

  12. Cystic Fibrosis cont. • 1989, discovered the CFTR gene • Have had some trials of adding healthy copies into cells • No cure yet • Cells that line the airway slough off periodically • Treatments must be repeated

  13. Severe Combined Immunodeficiency • Bubble Boy • 1976 David Vetter • Loss of a cytokine receptor (one gene is missing) • Can’t make B and T cells • X-linked

  14. SCID cont.. • Take bone marrow from patient • Use a virus to carry a new version of the gene into immune cells from the marrow • Re-implant into the patient • Began to generate further cells • Study done: 9/10 were completely restored

  15. STEM CELL • Embryonic stem cells • Can reproduce indefinitely in culture • Have the potential to grow into any cell type • Harvested from human embryos that are unused for fertility treatment • Embryo is destroyed

  16. At blastocyst stage: all cells are precursors to placenta, some to embryo • No exclusively embryonic cell population until 14 days.

  17. HeLa cells • Cells taken from Henrietta Lacks • Died from cancer on Oct. 4, 1951 • Cells taken from her cervical cancer mass • Immortal line of cells • Have been used for cancer research • The total number of cells that have been propagated in cell culture far exceeds the number of cells in her body

  18. Adult Stem Cells • Found in colon, brain, bone marrow • Naturally produce just one or a few types of cells • Limited life span in the lab • Avoid possible immune response • Already used for • Bone marrow • Grafts for cancer • Sometimes genetic blood disese • Cultivated skin grafts for burns* • Limbus grafts for cornea* • *a few cases

  19. Induced pluripotent stem cells (iPs) • Reprogram adult human cells to a pluripotent state (act like embryonic stem cells) • Introducing genes for 4 important stem cell transcription factors-into adult human fibroblasts using engineered retrovirus • OCT4, SOX2, NANOG, LIN28 • Easy to make • No embryo • Made from the individual patient

  20. Vaccines • Made by using one or more genes from a pathogen • Does not have disease-causing capability • Immune system mounts a defense against the protein • If come in contact again…ready to defend

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