1 / 29

Genetic engineering and cloning: Blessing or curse?

Genetic engineering and cloning: Blessing or curse?. Scientific information Caro: Genetic engineering Kathi: Cloning Indra: Stem cells. Genetic engineering. General information Process of ge Applications Research Human ge. General information. Direct manipulation of genes

RoyLauris
Download Presentation

Genetic engineering and cloning: Blessing or curse?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Genetic engineering and cloning: Blessing or curse? Scientific information Caro: Genetic engineering Kathi: Cloning Indra: Stem cells

  2. Genetic engineering • General information • Process of ge • Applications • Research • Human ge

  3. General information • Direct manipulation of genes • Changes structure / characteristics of genes • Different from all previous techniques - Applied quite successfully

  4. Process of genetic engineering • Isolation of the genes of interest • Insertion of the genes into a transfer vector • Transfer of the vector to the organism to be modified • Transformation of the cells of the organism (GMO) • Separation of the GMO from those that have not been successfully modified

  5. Applications - Synthetic human insulin • Hepatitis B vaccine • Food and vegetables

  6. Research • Loss of function experiments • Gain of function experiments • Tracking experiments • Expression studies

  7. Human genetic engineering • Individual genetic engineering • Germ-line genetic engineering  Infertile women

  8. Cloning • Definition • Molecular cloning • Cellular cloning • Somatic cell nuclear transfer (SCNT) • Organism cloning

  9. Cloning Definition: a) Biology: Producing a population of genetically-identical individuals. Examples: bacteria, insects, plants, which are asexual b) Biotechnology: 1) molecular cloning 2) cellular cloning

  10. Molecular cloning - Process of making multiple copies of a defined DNA sequence  amplify DNA fragments containing whole genes or DNA sequences such as promoters and randomly fragmented DNA Usage - biological experiments - practical applications: genetic fingerprints, protein production

  11. Premises • Isolation of sequence  sequence has to be capable of directing the propagation of itself and any linked sequences - specialised cloning vectors have to exist that allow manipulations such as protein expression and tagging

  12. The four steps of cloning 1. Fragmentation: breaking off a strand of DNA 2. ligation: gluing together pieces of DNA in a desired sequence 3. transfection: inserting the new pieces of DNA into cells 4. screening/selection: selecting out the manipulated cells

  13. Success rate - particularly low efficiency  need of identification procedures Identification of successfully manipulated cells - DNA fragment contains an antibiotic resistance marker - Cloning vectors contain colour selection markers which provide blue/white screening

  14. Cellular cloning - Process of deriving a population of cells from a single cell - clone distinct lineages of cell a) Unicellular organisms (bacteria, yeast): Cell inoculation of an appropriate medium  simple and efficient b) Multi-cellular organisms: Cells will not readily grow in standard media  arduous and difficult

  15. Tissue culture technique – Cloning rings • Using cloning rings - Single-cell suspension of cells are exposed to a mutagenic agent or drug • selection takes place - sterile cloning rings are placed over an individual colony and trypsin is added  Cloned cells are collected from inside the ring and transferred to a new vessel for further growth

  16. Somatic cell nuclear transfer (SCNT) and its usage - technique used to create clonal embryos • Nucleus took from a donor adult cell (somatic cell) and inserted into an egg cell, where the nucleus has been removed  meiosis leads to cloning - while clonal human blastocyst has been created, stem cell lines are isolated Usage - cloned embryos are used in research • mostly used in stem cell research - aim: to study human development and potentionally treat diseases

  17. Organism cloning - procedure to create a new multicellular organism, where all parts are genetically identical to each other - asexual method of reproduction - fertilization and inter-gamete contact does not occur - Asexual reproduction is a natural phenomenon ( many plants, some insects)

  18. Stem Cells: The Hope And The Hype By Nancy Gibbs (Time, 2006) • Hope • Politics and opinions • Ethical frontiers • Problems • Solutions • Adult stem cells • Nuclear-transfer embryos • Umbilical-cord cells

  19. Politics and opinions • Bush vetoed bill that would have expanded funding for human ESC (embryonic-stem-cell) research • science is in its infancy Opponents: - scientists can't destroy life in order to save it - promise of embryo research has been oversold • not just immoral but also unnecessary

  20. Politics and opinions Supporters: - eight-cell embryo doesn't count as human life (not when compared with the life it could help save) - cures can be derived from adult stem cells from bone marrow and umbilical cords - adult stem cells are still of limited use - leftover fertility-clinic embryos that would otherwise be thrown away - adult- and embryonic stem cells are needed to solve medical problems - Stem cell research is today a public spectacle in which data wrestle dogma

  21. Ethical frontiers - science is dense and the values tangled - adult-stem-cell research is morally fine but clinically limiting • embryonic cells possess the power to replicate indefinitely • Researchers extract knowledge from embryos that would otherwise be wasted but a much larger supply of fresh, healthy embryos than fertility clinics could ever provide is needed – less support from people

  22. The red tape slowed the science - Bush (prime-time speech, 2001): federal money to ESC lines – no new lines - states support labs while private biotech firms are free to create (no regulations) - scientists who work with the approved “presidential” lines are in frustration - can't do what newer cell lines can do - presidential lines are wasting money as well as time - Even if Bush hadn't vetoed the bill, it wouldn't have solved the supply problems – embryos of infertile couples tend to be weaker

  23. Problems - in wake of Bush's original order, Harvard decided to use private funding to create 100 new cell lines – diversity is needed - new technique: develop new cell lines through somatic cell nuclear transfer (therapeutic cloning) • cells would match the patient's DNA • another technique: yield embryos that serve as the perfect disease in a dish, revealing how a disease unfolds from the very first hours - no real success

  24. Solutions - scientists are searching for another source of cells that is less ethically troublesome - gene is removed before cell is fused with egg  critics - Method: taking an adult skin cell, exposing it to four growth factors in a petri dish and transforming it into an embryo-like entity that could produce stem cells - biotech industry is closest to human trials

  25. The risk on the new frontier - patient safety - regulators want data on how the cells will behave in the human body - stem cells have a talent from turning into tumors

  26. Adult stem cells - cord-blood cells have a lot of promise for tissue repair and regeneration – it will take 10 to 20 years - scientists could transform adult stem cells from fat tissue into smooth-muscle cells, which assist in the function of numerous organs - ability to self-renew - theoretically immortal and can continue to divide forever if provided with enough nutrients Traits - exist in many major tissues, including the blood, skin and brain - can be coaxed to produce more cells of a specific lineage and do not have to be extracted from embryos - can generate only a limited number of cell types - difficult to grow in culture

  27. Nuclear-transfer embryos • stem cells can be custom-made by inserting a patient's skin cell into a hollowed human egg - process has not yet been successfully completed with human cells - requires an enormous amount of fresh human eggs

  28. Umbilical-cord cells - made up of blood stem cells - contain stem cells that can turn into bone, cartilage, heart muscle, brain and liver tissue - harvested without the need for embryos - not very long and doesn't hold enough cells to treat an adult

More Related