Published on

Published in: Education
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide


  1. 1. CLONING<br />An Overview<br />
  2. 2. GROUP MEMBERS<br />HASSAN TARIQ (2008-EE-180)<br /><ul><li>Introduction and Overview
  3. 3. Cloning in Nature</li></ul>ZAIR HUSSAIN (2008-EE-177)<br /><ul><li>History of Cloning</li></ul>SAQIB SAEED (2008-EE-168)<br /><ul><li>How scientists clone cells</li></ul>UMAIR MAQBOOL (2008-EE-178)<br /><ul><li>Stem cells technology
  4. 4. Benefits of Cloning</li></li></ul><li>Introduction and overview<br />
  5. 5. Introduction<br />Cloning: Creating copies of living matter<br />The term clone (from the Greek word klōn, meaning “twig”) had already been in use <br /><ul><li>since the beginning of the 20th century
  6. 6. in reference to plants</li></ul>Clones have identical genetic makeup<br />Abundant in nature<br />Used by scientists to generate organisms with valuable traits<br />
  7. 7. Historical Perspective<br />Farmers started using it thousands of years ago<br />Revolutionized in late 20th Century with the advent of genetic engineering<br />
  8. 8. Cloning in Animals<br />To generate animals with desirable traits<br />To bolster endangered species<br />Maybe in near future, extinct animals can be resurrected<br />
  9. 9. Industrial Perspective<br />Production of bacteria which can clean up environmental contamination<br />Animals which can produce commercial ingredients e.g. protein <br />
  10. 10. Importance for Humans<br />Promises great advances in medicine<br />Biomedical scientists plan to create animals with human diseases, so that cures can be experimented safely<br />
  11. 11. Cloning in nature<br />
  12. 12. In Bacteria and Plants <br />Originated in nature<br />Most organisms reproduce asexually<br />Unicellular organisms reproduce by fission, a cloning method<br />Plants like strawberries clone by producing runners<br />
  13. 13. In Animals and Mammals<br />Some species of fish, shrimps, lizards and frogs produce by parthenogenesis- from Greek word parthenos (“virgin”) and genesis (“birth”)<br />Clones in mammals- genetic copies of each other<br />
  14. 14. History of cloning<br />
  15. 15. Initial Efforts<br />1800’s- First try of using undifferentiated cells<br /><ul><li> Hans Dreisch separated a sea urchin embryo when it was just two cells
  16. 16. Both cells grew to adults</li></ul>Early 1900’s- Hans Spemann extended Dreisch’s work to salamanders <br /><ul><li>Determined that nucleus from embryo cell could direct the development of a complete organism
  17. 17. Published his results in 1938
  18. 18. Proposed a “fantastical” experiment</li></li></ul><li>Early Frog Experiments<br />1952- Spemann’s idea realized by Robert Briggs and Thomas King<br /><ul><li> Used cell nuclear transfer to insert DNA from a frog embryo cell into an enucleated frog egg
  19. 19. Resulting embryo grew into an adult
  20. 20. Early experiments using cell nuclear transfer were successful only when donor DNA was taken from an embryonic cell</li></li></ul><li>Early Frog Experiments (Gurdon’s Method)<br />1962- John Gurdon began cloning experiments using non-embryonic cells<br /><ul><li> Cells from intestinal lining of tadpoles
  21. 21. Exposed a frog egg to ultraviolet light, which destroyed its nucleus
  22. 22. Removed the nucleus from the tadpole intestinal cell and implanted it in the enucleated egg
  23. 23. Egg grew into a tadpole that was genetically identical to the DNA-donating tadpole</li></li></ul><li>Impact of Gurdon’s Research<br />Gurdon’s experiments captured the attention of the scientific community <br />Tools and techniques he developed for nuclear transfer are still used today <br />1963- J. B. S. Haldane, in describing Gurdon’s results, became one of the first to use the word clone in reference to animals<br />
  24. 24. Glitches of Gurdon’s Method<br />Tadpoles cloned in Gurdon’s experiments never survived to adulthood <br />Scientists now believe that cells used may not have been differentiated cells<br />
  25. 25. Mammal Cloning (Initial Efforts)<br />Scientists turned their attention to cloning mammals <br />Proved even more complex than earlier cloning experiments on invertebrates and amphibians <br />1977- Karl Illmensee reported cloning mice from cells derived from early embryos <br /><ul><li>Illmensee’s findings were largely discredited because he used questionable laboratory techniques </li></ul>Agricultural researchers tried to clone cattle using somatic cell nuclear transfer, but failed<br />
  26. 26. Mammal Cloning(Breakthrough)<br />1984- First mammal cloned<br /><ul><li> Danish biologist Steen Willadsen
  27. 27. Working at Cambridge University in England</li></ul>Used nuclear transfer with DNA from early embryonic cells<br />Two years later, a team of researchers at the University of Wisconsin cloned a cow through a similar approach<br />
  28. 28. Mammal Cloning (Further Developments)<br />1990’s- Cloning techniques advanced rapidly<br />1995- Two lambs cloned<br /><ul><li>By Keith Campbell and Ian Wilmut at the Roslin Institute
  29. 29. From embryonic cells; named Megan and Morag
  30. 30. Scientists were able to keep the embryonic cells alive in culture for some time before beginning the cloning procedure</li></ul>Enabled scientists to modify an embryonic cell’s genes in culture before cloning <br />Genetically modified livestock can be produced<br />
  31. 31. Megan and Morag<br />
  32. 32. HOW SCIENTISTS CLONE CELLS…<br />Blastomere separationBlastocyst divisionsomatic cell nuclear transfer<br />
  33. 33. Up till 1950’s<br />Initial Efforts- Letting a single cell divide in a laboratory dish by ‘mitosis’<br />Complex Techniques- Using animal embryos<br />1950’s- Using cells that haven’t been differentiated yet (totipotent)<br />
  35. 35. Blastomere Separation<br />Fertilize an egg cell with a sperm cell in a laboratory dish till embryo is of about 4 cells<br />Outer coating of embryo removed<br />Placed in a solution to separate individual cells (Blastomeres)<br />Each blastomere cultured separately<br />Embryos implanted into surrogate mothers<br />
  37. 37. Blastocyst Division<br />Fertilized cell allowed to divide till mass is 30-150 cells (Blastocyst)<br />Split Blastocyte into two<br />Each half implanted in a surrogate mother<br />Creation of identical twins<br />
  39. 39. Somatic Cell Nuclear Transfer (Overview)<br />Use cells of only ONE parent<br />Somatic Cell (any body cell EXCEPT an egg or a sperm)<br />Enucleated Egg Cell (egg with its nucleus removed)<br />Merge both cells via fusion<br />Only applicable on immature cells (either embryonic, or of young animals)<br />
  40. 40. Somatic Cell Nuclear Transfer (Breakthrough- Birth of Dolly)<br />In 1996, by improved somatic cell nuclear transfer method<br />Donor cell made quiescent (less active)<br />Transfer of genetic material from udder cell to an enucleated cell (from a second sheep)<br />Resulting embryo was implanted into the uterus of a third sheep<br />Now donor cells can be taken from adult animals<br />
  41. 41. Egg Donor<br />
  42. 42. Genetic Donor<br />
  43. 43. Enucleated Cell<br />
  44. 44. Embryo Development<br />
  45. 45. Embryo Implantation<br />
  46. 46. Birth<br />
  47. 47. Somatic Cell Nuclear Transfer (Glitches)<br />All genes are NOT in nucleus, so all genes of the clone are NOT those of the donor<br />Since every organism is influenced by, both genes and the environment, so the clone’s life will be different from that of the parent<br />
  48. 48. Stem cells and cloning<br />
  49. 49. Basics<br />At Blastocyte stage, embryonic cells can divide into ALL types of cells needed by the organism<br />Scientists separate these cells and coax them to divide under special conditions (so that they can form any cell type)<br />Humans maintain some stem cells in some tissue of body till death. But with aging, they lose ability to transform into different cell types (cells from bone marrow is exception)<br />
  50. 50. Benefits<br />Can be used to cure diseases<br />If a patient receives stem cells cloned containing his own genetic material, then his/ her immune system would not reject them as foreign material<br />Research going on to find cure for Parkinson’s, paralysis, damaged heart muscles, arthritis and diabetes mellitus<br />
  51. 51. Results<br />Still in experimental stage<br />First clinical trial of curing patients suffering from Parkinson’s produced mixed results<br /><ul><li> Patients over 60 years old reported no improvement
  52. 52. Younger patients reported some improvement, but 15% of them sport irreversible side effects, like uncontrollable twitching</li></li></ul><li>Risks<br />If some error occurred during cloning, then all resulting cells will have same error<br />However, in 2002, scientists at Rutgers University found comparatively fewer genetic mutations<br />Risk of transferring disease via stem cells<br /><ul><li> Typically, scientists culture human stem cells with mouse cells
  53. 53. Mouse cells have some unknown nutrient that keeps human stem cells alive
  54. 54. So human cells can easily be infected by mouse cells</li></li></ul><li>Benefits <br />of <br />Cloning<br />
  55. 55. Benefits of Animal Cloning<br />In Agriculture<br /><ul><li> Cloned cattle could produce higher yield of milk & meat
  56. 56. Can also produce drugs at commercial level</li></ul>In Laboratory<br /><ul><li> Create animals with human diseases
  57. 57. Can test cures on them safely</li></li></ul><li>Cloning Endangered & Extinct Species<br />2001- Gaur (endangered ox of South-East Asia) cloned successfully<br />Plan to revive extinct species by cloning<br /><ul><li>Cells of last Spanish ibex (mountain goat) preserved for the same purpose</li></ul>Prerequisites<br /><ul><li>Cell with intact nucleus
  58. 58. Surrogate mother needed with similar genetic makeup, to implant the embryo</li></li></ul><li>Can Humans Be Cloned…….?<br />Impossible up till now<br /> In human embryo, number of cells become twice after every 24 hours<br /><ul><li> Not achieved yet in laboratory </li></ul>Not enough funding due to its controversial nature<br />
  59. 59. Controversies<br />People do not consider plant cloning as cloning: Main opposition is against animal cloning<br />Arguments:<br /><ul><li> Man should not play God
  60. 60. Will increase social gaps, as babies with special traits, like beauty, athleticism, or intelligence can be created</li>