Biology - Chp 13 - Genetic Engineering - PowerPoint


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Biology - Chp 13 - Genetic Engineering - PowerPoint

  1. 1. Chapter 13 Genetic Engineering
  2. 2. 13 – 1 Changing the Living World
  3. 3. Selective Breeding <ul><li>Allowing only those animals with desired characteristics to produce the next generation </li></ul>
  4. 4. <ul><li>Humans use selective breeding, which takes advantage of naturally occurring genetic variation in plants, animals, and other organisms, to pass desired traits on to the next generation of organisms </li></ul><ul><li>Nearly all domestic animals and plants have been produced by selective breeding </li></ul>
  5. 5. Hybridization <ul><li>Crossing dissimilar individuals to bring together the best of both organisms </li></ul><ul><li>Hybrids are often hardier than their parents </li></ul>
  6. 16. Inbreeding <ul><li>The continued breeding of individuals with similar characteristics </li></ul>
  7. 17. <ul><li>The goal is to maintain the desired characteristics of a line of organisms </li></ul><ul><li>There are always risks to inbreeding </li></ul><ul><li>Because most members of a species are genetically similar, there is a chance that a cross between two individuals will bring together two recessive alleles for a genetic defect </li></ul>
  8. 18. Increasing Variations <ul><li>Breeders can increase the genetic variation in a population by inducing mutations </li></ul><ul><li>You can increase the mutation rate by using the following… </li></ul><ul><li>Radiation </li></ul><ul><li>Chemicals </li></ul><ul><li>Most mutations can be harmful but sometimes they can bring desirable characteristics </li></ul>
  9. 19. Producing New Kinds of Bacteria <ul><li>Using this method of inducing mutations, scientists have made many useful strains of bacteria </li></ul><ul><li>Ex.) bacteria that can digest oil </li></ul>
  10. 20. Producing New Kinds of Plants <ul><li>Scientists use drugs that prevent chromosomal separation during meiosis </li></ul><ul><li>This results in cells that have double or triple the normal number of chromosomes called… </li></ul><ul><li>Polyploidy </li></ul>
  11. 21. 13 – 2 Manipulating DNA
  12. 22. <ul><li>Until recently, animal and plant breeders could not modify the genetic code of living things </li></ul><ul><li>They were limited by the variation that exists in nature </li></ul><ul><li>Today scientists can go right to the genetic code and re-write an organisms DNA, transfer genes at will from one organism to another and design new living things to meet specific needs </li></ul>
  13. 23. Different techniques are used to… <ul><li>Extract DNA from cells </li></ul><ul><li>Cut DNA into smaller pieces </li></ul><ul><li>Identify the sequence of bases in a DNA molecule </li></ul><ul><li>Make unlimited copies of DNA </li></ul>
  14. 24. Genetic Engineering <ul><li>Making changes in the DNA code of a living organism </li></ul>
  15. 25. DNA Extraction <ul><li>DNA can be extracted from most cells by a simple chemical procedure </li></ul><ul><li>The cells are opened and the DNA is separated from other parts of the cell </li></ul>
  16. 26. Cutting DNA <ul><li>DNA molecules are much too large to be analyzed so biologists cut them into smaller fragments </li></ul>
  17. 27. Restriction Enzymes <ul><li>Cuts DNA at a specific sequence of nucleotides </li></ul>
  18. 28. Separating DNA <ul><li>Electrophoresis </li></ul><ul><li>Mixture of DNA fragments is placed at one end of a porous gel </li></ul><ul><li>Electric charge is applied </li></ul><ul><li>Negatively charged DNA molecules move towards positive ends </li></ul><ul><li>Small fragments move faster and farther than larger ones </li></ul>
  19. 30. Using the DNA Sequence <ul><li>Knowing the sequence of an organisms DNA allows researchers to study specific genes, to compare them with the genes of other organisms, to try to discover the functions of different genes and gene combinations </li></ul>
  20. 31. Cutting and Pasting <ul><li>Short sequences can be assembled using laboratory machines known as DNA synthesizers </li></ul><ul><li>“ Synthetic” sequences can be joined to “natural” ones using enzymes that splice DNA together </li></ul><ul><li>The same enzymes make it possible to take a gene from one organism and attach it to the DNA of another organism </li></ul>
  21. 32. Recombinant DNA <ul><li>DNA molecules produced by combining DNA from other sources </li></ul>
  22. 34. Making Copies <ul><li>In order to study genes, biologists often need to make copies of a particular gene </li></ul>
  23. 35. Polymerase Chain Reaction (PCR) <ul><li>Technique used to copy DNA </li></ul><ul><li>Invented by American scientists Kary Mullis </li></ul><ul><li>Autobiography – Dancing Naked in the Mind Field </li></ul>
  24. 37. How PCR Works <ul><li>Add a primer to the portions of a sequence you want to copy </li></ul><ul><li>Heat DNA to separate its two strands, then cool to let the primers bind to single-stranded DNA </li></ul><ul><li>DNA polymerase starts making copies of the region between the primers </li></ul>
  25. 39. Do Now <ul><li>The following Do Now questions are actual regents questions from previous years… </li></ul>
  26. 43. 13 – 3 Cell Transformation
  27. 44. <ul><li>It would do little good to modify a DNA molecule in a test tube if it were not possible to put that DNA back into a living cell and make it work </li></ul><ul><li>During transformation, a cell takes in DNA from outside the cell. This external DNA becomes part of the cells DNA </li></ul>
  28. 45. Transforming Bacteria <ul><li>1. The foreign DNA is first joined to a small circular DNA molecule known as a plasmid </li></ul><ul><li>Plasmid – small circular DNA molecule </li></ul><ul><li>Easily replicated </li></ul>
  29. 46. Transforming Bacteria <ul><li>2. The plasmid has a genetic marker – a gene that makes it possible to distinguish bacteria that carry the plasmid (and foreign DNA) from those that don’t </li></ul>
  30. 48. Transforming Plant Cells <ul><li>Many plant cells can be transformed by using a bacteria that usually produces tumors in a plants cells </li></ul><ul><li>Researchers have inactivated the tumor producing gene and inserted a piece of foreign DNA into the plasmid </li></ul><ul><li>The recombinant plasmid can then be used to infect plant cells </li></ul><ul><li>If transformation is successful, the recombinant DNA is integrated into one of the chromosomes of the cell </li></ul>
  31. 50. Transforming Animal Cells <ul><li>Animal cells can be transformed in the same ways as plant cells </li></ul><ul><li>Many egg cells are large enough that DNA can be directly injected into the nucleus </li></ul><ul><ul><li>Once inside enzymes normally responsible for DNA repair and recombination may help insert the foreign DNA into the chromosomes of the injected cell </li></ul></ul>
  32. 51. Knocking Out Genes <ul><li>Recently, it has become possible to eliminate particular genes by careful design of the DNA molecules that are used for transformation </li></ul><ul><li>DNA molecules can be constructed with two ends that will sometimes recombine with specific sequences in the host chromosome </li></ul><ul><li>Once they do, the host gene may be lost or specifically replaced with a new gene </li></ul><ul><li>This makes it possible to pinpoint the specific functions of genes </li></ul>
  33. 53. Do Now <ul><li>2 More old regents questions on genetic engineering… </li></ul>
  34. 56. 13 – 4 Applications of Genetic Engineering
  35. 57. Transgenic organisms <ul><li>Organisms that contain genetic information from other species </li></ul><ul><li>Q: How does one do this? </li></ul><ul><li>A: Take a gene from one organism and place it in another </li></ul>
  36. 58. <ul><li>This idea has sparked the new booming industry of biotechnology </li></ul>
  37. 59. Fun With Fireflies <ul><li>There is an enzyme that makes fireflies glow </li></ul><ul><li>Luciferase </li></ul><ul><li>Could we take a gene out of an animal and put it in something else? </li></ul><ul><li>Could we get things that don’t glow, to glow </li></ul>
  38. 60. Glowing Tobacco Plant <ul><li>Put luciferase gene in a tobacco plant and you can get a glowing tobacco plant </li></ul>
  39. 64. Glow - Fish
  40. 66. Glow - Mice
  41. 69. Transgenic Microorganisms <ul><li>Before: Diabetics had to use insulin from cadavers </li></ul><ul><li>Now: We make bacteria that produce human proteins such as insulin, growth hormone, clotting factor </li></ul><ul><li>Future: Bacteria may produce substances to fight cancer, make raw materials for plastic and fibers </li></ul>
  42. 70. Transgenic Animals <ul><li>There are currently no transgenic animals that are approved for human consumption. </li></ul><ul><li>But there are a lot of experimental studies being done </li></ul>
  43. 71. Transgenic Animals <ul><li>Mice susceptible to cancer </li></ul><ul><li>Mice made to have human immune systems </li></ul><ul><li>Livestock with growth hormone </li></ul><ul><li>Chickens resistant to bacterial infections that cause us food poisoning </li></ul><ul><li>Mad cow resistant cows </li></ul><ul><li>Sheep and pigs that produce our proteins </li></ul><ul><li>Spider web goats </li></ul>
  44. 72. Spider Web Goats? <ul><li>Take the gene for making spider web silk </li></ul>
  45. 73. <ul><li>Put it in a goat </li></ul><ul><li>Then milk it </li></ul><ul><li>Extract the spider web silk in large quantities… </li></ul><ul><li>And we could have… </li></ul>
  46. 74. <ul><li>The best bullet proof vest ever! </li></ul><ul><li>Strongest steel cables </li></ul><ul><li>And much more… </li></ul>
  47. 75. Transgenic Plants <ul><li>Already here, already controversial </li></ul><ul><li>Here are some facts and myths </li></ul><ul><li>There are only six categories of trangenic plants </li></ul>
  48. 76. Soy Beans <ul><li>50 percent of soy beans today are genetically modified </li></ul>
  49. 77. Corn <ul><li>25 percent of corn is genetically modified </li></ul>
  50. 78. Insect Resistant <ul><li>The bulk of both soy beans and corn that is genetically modified is modified to have a natural insecticide </li></ul>
  51. 79. Herbicide resistant <ul><li>Others resist weed killing chemicals </li></ul>
  52. 80. The other categories <ul><li>Virus resistant </li></ul><ul><li>Delayed fruit ripening </li></ul><ul><li>Altered oil control </li></ul><ul><li>Pollen control </li></ul>
  53. 81. Golden Rice <ul><li>Rice genetically modified to have added vitamins </li></ul><ul><li>Not marketed to the public yet </li></ul>
  54. 82. Transgenic Plant Myths <ul><li>The fish tomato and the fish berry </li></ul><ul><li>Genetically modify plants to have a fish gene that makes them able to live in colder temperatures </li></ul><ul><li>Experimentally tested, but never worked </li></ul>
  55. 83. Still controversial <ul><li>Soybeans with brazil nut allergens </li></ul><ul><li>Terminator seeds </li></ul>
  56. 84. A Rising Trend <ul><li>As more and more farmers are realizing the efficiency of these GM plants, the more they will be used </li></ul>
  57. 85. Clone <ul><li>A member of a population of genetically identical cells produced by a single cell </li></ul>
  58. 86. How to get a clone in 4 easy steps <ul><li>1. Remove the nucleus of an egg </li></ul>
  59. 87. How to get a clone in 4 easy steps <ul><li>2. Fuse egg with a cell taken from another organism </li></ul><ul><li>3. Place in the uterus of a foster mother </li></ul><ul><li>4. Foster mother gives birth to cloned baby </li></ul>
  60. 88. Donor Nucleus These two cells are fused using an electric shock. Fused Cell The fused cell begins dividing normally. Embryo The embryo is placed in the uterus of a foster mother. The embryo develops normally into a lamb—Dolly Egg Cell An egg cell is taken from an adult female sheep. The nucleus of the egg cell is removed.
  61. 89. Dolly <ul><li>First time this was done in a mammal was in 1997 </li></ul><ul><li>A gigantic scientific breakthrough at the time </li></ul>
  62. 90. We have also cloned <ul><li>Cows </li></ul><ul><li>Pigs </li></ul><ul><li>Mice </li></ul><ul><li>Cats </li></ul><ul><li>Dogs </li></ul><ul><li>Horse </li></ul><ul><li>Monkey </li></ul>
  63. 91. Starlight…guess where it was cloned
  64. 92. The cutest clone <ul><li>First cloned cat </li></ul><ul><li>“ CC ” </li></ul>
  65. 93. Cloned Mice Nucleus Donor Egg Donor Surrogate Mother Cloned babies
  66. 94. Female gives birth to her own dam twin! <ul><li>Dam = female horse </li></ul>
  67. 95. The worlds first cloned dog
  68. 96. The latest clones <ul><li>Will be used to study stem cells </li></ul><ul><li>And animal to human transplants </li></ul>
  69. 97. Breaking News in the Cloning World! <ul><li>Scientists just announced today that for the first time, they have successfully cloned a rhesus monkey embryo </li></ul>
  70. 98. Pros and Cons of Cloning <ul><li>Pros </li></ul><ul><li>Saving endangered species </li></ul><ul><li>Transgenic animals for human consumption </li></ul><ul><li>Organ and tissue transplants </li></ul><ul><li>Cons </li></ul><ul><li>Cloned animals have genetic defects </li></ul><ul><li>Health problems </li></ul>
  71. 99. Should we reproductively clone humans? <ul><li>No! </li></ul><ul><li>It took 188 tries on Dolly </li></ul><ul><li>Success rate of .4 on the horse </li></ul><ul><li>Success rate of 1.6 on the dog </li></ul><ul><li>How many humans would die before this worked? </li></ul>