1. CLONING An Overview

6. in reference to plantsClones have identical genetic makeup Abundant in nature Used by scientists to generate organisms with valuable traits

7. Historical Perspective Farmers started using it thousands of years ago Revolutionized in late 20th Century with the advent of genetic engineering

8. Cloning in Animals To generate animals with desirable traits To bolster endangered species Maybe in near future, extinct animals can be resurrected

9. Industrial Perspective Production of bacteria which can clean up environmental contamination Animals which can produce commercial ingredients e.g. protein

10. Importance for Humans Promises great advances in medicine Biomedical scientists plan to create animals with human diseases, so that cures can be experimented safely

11. Cloning in nature

12. In Bacteria and Plants Originated in nature Most organisms reproduce asexually Unicellular organisms reproduce by fission, a cloning method Plants like strawberries clone by producing runners

13. In Animals and Mammals Some species of fish, shrimps, lizards and frogs produce by parthenogenesis- from Greek word parthenos (“virgin”) and genesis (“birth”) Clones in mammals- genetic copies of each other

14. History of cloning

17. Published his results in 1938

19. Resulting embryo grew into an adult

21. Exposed a frog egg to ultraviolet light, which destroyed its nucleus

22. Removed the nucleus from the tadpole intestinal cell and implanted it in the enucleated egg

24. Glitches of Gurdon’s Method Tadpoles cloned in Gurdon’s experiments never survived to adulthood Scientists now believe that cells used may not have been differentiated cells

27. Working at Cambridge University in EnglandUsed nuclear transfer with DNA from early embryonic cells Two years later, a team of researchers at the University of Wisconsin cloned a cow through a similar approach

29. From embryonic cells; named Megan and Morag

30. Scientists were able to keep the embryonic cells alive in culture for some time before beginning the cloning procedureEnabled scientists to modify an embryonic cell’s genes in culture before cloning Genetically modified livestock can be produced

31. Megan and Morag

32. HOW SCIENTISTS CLONE CELLS… Blastomere separationBlastocyst divisionsomatic cell nuclear transfer

33. Up till 1950’s Initial Efforts- Letting a single cell divide in a laboratory dish by ‘mitosis’ Complex Techniques- Using animal embryos 1950’s- Using cells that haven’t been differentiated yet (totipotent)

34. HOW SCIENTISTS CLONE CELLS… BLASTOMERE SEPARATION BLASTOCYST DIVISION SOMATIC CELL NUCLEAR TRANSFER

35. Blastomere Separation Fertilize an egg cell with a sperm cell in a laboratory dish till embryo is of about 4 cells Outer coating of embryo removed Placed in a solution to separate individual cells (Blastomeres) Each blastomere cultured separately Embryos implanted into surrogate mothers

36. HOW SCIENTISTS CLONE CELLS… BLASTOMERE SEPARATION BLASTOCYST DIVISION SOMATIC CELL NUCLEAR TRANSFER

37. Blastocyst Division Fertilized cell allowed to divide till mass is 30-150 cells (Blastocyst) Split Blastocyte into two Each half implanted in a surrogate mother Creation of identical twins

38. HOW SCIENTISTS CLONE CELLS… BLASTOMERE SEPARATION BLASTOCYST DIVISION SOMATIC CELL NUCLEAR TRANSFER

39. Somatic Cell Nuclear Transfer (Overview) Use cells of only ONE parent Somatic Cell (any body cell EXCEPT an egg or a sperm) Enucleated Egg Cell (egg with its nucleus removed) Merge both cells via fusion Only applicable on immature cells (either embryonic, or of young animals)

40. Somatic Cell Nuclear Transfer (Breakthrough- Birth of Dolly) In 1996, by improved somatic cell nuclear transfer method Donor cell made quiescent (less active) Transfer of genetic material from udder cell to an enucleated cell (from a second sheep) Resulting embryo was implanted into the uterus of a third sheep Now donor cells can be taken from adult animals

41. Egg Donor

42. Genetic Donor

43. Enucleated Cell

44. Embryo Development

45. Embryo Implantation

46. Birth

47. Somatic Cell Nuclear Transfer (Glitches) All genes are NOT in nucleus, so all genes of the clone are NOT those of the donor Since every organism is influenced by, both genes and the environment, so the clone’s life will be different from that of the parent

48. Stem cells and cloning

49. Basics At Blastocyte stage, embryonic cells can divide into ALL types of cells needed by the organism Scientists separate these cells and coax them to divide under special conditions (so that they can form any cell type) 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)

50. Benefits Can be used to cure diseases If a patient receives stem cells cloned containing his own genetic material, then his/ her immune system would not reject them as foreign material Research going on to find cure for Parkinson’s, paralysis, damaged heart muscles, arthritis and diabetes mellitus

53. Mouse cells have some unknown nutrient that keeps human stem cells alive

60. Will increase social gaps, as babies with special traits, like beauty, athleticism, or intelligence can be created