Genetic engineering and cloning: Blessing or curse?

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

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

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

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

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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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)

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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