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  • Figure 12.2 Humulin, human insulin produced by genetically modified bacteria
  • Figure 12.3 A factory that produces genetically engineered insulin
  • Figure 12.4 Genetically modified corn
  • Figure 12.5 Genetically modified rice
  • Figure 12.7 Bacterial plasmids
  • Figure 12.8 Using recombinant DNA technology to produce useful products (Step 8)
  • Figure 12.9 Cutting and pasting DNA (Step 1)
  • Figure 12.9 Cutting and pasting DNA (Step 2)
  • Figure 12.9 Cutting and pasting DNA (Step 3)
  • Figure 12.9 Cutting and pasting DNA (Step 4)
  • Figure 12.12 A DNA synthesizer
  • Figure 12.13 Overview of DNA profiling (Step 1)
  • Figure 12.13 Overview of DNA profiling (Step 2)
  • Figure 12.13 Overview of DNA profiling (Step 3)
  • Figure 12.15 DNA amplification by PCR
  • Figure 12.16 Short tandem repeat (STR) sites
  • Figure 12.17 Gel electophoresis of DNA molecules (Step 1)
  • Figure 12.17 Gel electophoresis of DNA molecules (Step 2)
  • Figure 12.17 Gel electophoresis of DNA molecules (Step 3)
  • Figure 12.18 Visualizing STR fragment patterns
  • Table 12.1 Some Important Sequenced Genomes
  • Figure 12.20 The fight against Parkinson's disease
  • Figure 12.24 One approach to human gene therapy (Step 1)
  • Figure 12.24 One approach to human gene therapy (Step 2)
  • Figure 12.24 One approach to human gene therapy (Step 3)
  • Figure 12.25 Maximum-security laboratory
  • Figure 12.26 Opposition to genetically modified organisms (GMOs)
  • Figure 12.27 Personalized genetic testing
  • Student Misconceptions and Concerns
    1. The many issues raised in this chapter are of great potential significance and remain unresolved. An informed debate about rights, responsibilities, and possibilities is currently engaged in modern society regarding these scientific issues.
    The Genetic Information Nondiscrimination Act was passed in May 2008. Details about this important legislation can be found at www.ornl.gov/sci/techresources/Human_Genome/elsi/legislat.shtml.
    Teaching Tips
    1. Genetically engineered organisms are controversial, creating various degrees of concern. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of genetic engineering. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms.
    2. A person was recently heard to declare their opposition to GM food by stating “I do not want any DNA in my food.” You might want to have your students respond to this person’s concerns.
  • Figure 12.UN2 Summary: DNA profiling
  • Figure 12.UN3 Summary: human gene therapy
  • 12 lecture presentation0

    1. 1. Biology and Society: DNA, Guilt, and Innocence • DNA profiling is the analysis of DNA samples that can be used to determine whether the samples come from the same individual. • DNA profiling can therefore be used in courts to indicate if someone is: – Guilty – Innocent © 2010 Pearson Education, Inc.
    2. 2. © 2010 Pearson Education, Inc. • DNA technology has led to other advances in the: – Creation of genetically modified crops – Identification and treatment of genetic diseases
    3. 3. © 2010 Pearson Education, Inc. • Biotechnology today means the use of DNA technology, methods for: – Studying and manipulating genetic material – Modifying specific genes – Moving genes between organisms
    4. 4. © 2010 Pearson Education, Inc. • Recombinant DNA is formed when scientists combine nucleotide sequences (pieces of DNA) from two different sources to form a single DNA molecule. • Recombinant DNA technology is widely used in genetic engineering, the direct manipulation of genes for practical purposes.
    5. 5. © 2010 Pearson Education, Inc. Applications: From Humulin to Foods to “Pharm” Animals • By transferring the gene for a desired protein into a bacterium or yeast, proteins that are naturally present in only small amounts can be produced in large quantities.
    6. 6. © 2010 Pearson Education, Inc. Making Humulin • In 1982, the world’s first genetically engineered pharmaceutical product was sold. • Humulin, human insulin: – Was produced by genetically modified bacteria – Was the first recombinant DNA drug approved by the FDA – Is used today by more than 4 million people with diabetes
    7. 7. Figure 12.2
    8. 8. © 2010 Pearson Education, Inc. • Today, humulin is continuously produced in gigantic fermentation vats filled with a liquid culture of bacteria.
    9. 9. Figure 12.3
    10. 10. © 2010 Pearson Education, Inc. • DNA technology is used to produce medically valuable molecules, including: – Human growth hormone (HGH) – The hormone EPO, which stimulates production of red blood cells – Vaccines, harmless variants or derivatives of a pathogen used to prevent infectious diseases
    11. 11. © 2010 Pearson Education, Inc. Genetically Modified (GM) Foods • Today, DNA technology is quickly replacing traditional plant- breeding programs. • Scientists have produced many types of genetically modified (GM) organisms, organisms that have acquired one or more genes by artificial means. • A transgenic organism contains a gene from another organism, typically of another species.
    12. 12. © 2010 Pearson Education, Inc. • In the United States today, roughly one-half of the corn crop and over three-quarters of the soybean and cotton crops are genetically modified. • Corn has been genetically modified to resist insect infestation.
    13. 13. Figure 12.4
    14. 14. © 2010 Pearson Education, Inc. • “Golden rice” has been genetically modified to produce beta- carotene used in our bodies to make vitamin A.
    15. 15. Figure 12.5
    16. 16. © 2010 Pearson Education, Inc. • DNA technology: – May eventually replace traditional animal breeding but – Is not currently used to produce transgenic animals sold as food • Meat may come from livestock that receive genes that produce: – Larger muscles or – Healthy omega-3 fatty acids instead of less healthy fatty acids (already done in 2006 in pigs)
    17. 17. © 2010 Pearson Education, Inc. Recombinant DNA Techniques • Bacteria are the workhorses of modern biotechnology. • To work with genes in the laboratory, biologists often use bacterial plasmids, small, circular DNA molecules that are separate from the much larger bacterial chromosome.
    18. 18. Plasmids Bacterial chromosome Remnant of bacterium ColorizedTEM Figure 12.7
    19. 19. © 2010 Pearson Education, Inc. • Plasmids: – Can easily incorporate foreign DNA – Are readily taken up by bacterial cells – Can act as vectors, DNA carriers that move genes from one cell to another – Are ideal for gene cloning, the production of multiple identical copies of a gene-carrying piece of DNA
    20. 20. © 2010 Pearson Education, Inc. • Recombinant DNA techniques can help biologists produce large quantities of a desired protein. Blast Animation: Genetic Recombination in Bacteria Animation: Cloning a Gene
    21. 21. Plasmid Bacterial cell Isolate plasmids. Some uses of genes Gene for pest resistance Gene for toxic-cleanup bacteria Genes may be inserted into other organisms. Find the clone with the gene of interest. The gene and protein of interest are isolated from the bacteria. Clone the bacteria. Recombinant bacteriaBacterial clone Gene of interest Recombinant DNA plasmids Bacteria take up recombinant plasmids. Harvested proteins may be used directly. Some uses of proteins Protein for “stone-washing” jeans DNA Cell containing the gene of interest Protein for dissolving clots Isolate DNA. DNA fragments from cell Cut both DNAs with same enzyme. Gene of interest Other genes Mix the DNAs and join them together. Figure 12.8-8
    22. 22. A Closer Look: Cutting and Pasting DNA with Restriction Enzymes • Recombinant DNA is produced by combining two ingredients: – A bacterial plasmid – The gene of interest • To combine these ingredients, a piece of DNA must be spliced into a plasmid. © 2010 Pearson Education, Inc.
    23. 23. © 2010 Pearson Education, Inc. • This splicing process can be accomplished by: – Using restriction enzymes, which cut DNA at specific nucleotide sequences, and – Producing pieces of DNA called restriction fragments with “sticky ends” important for joining DNA from different sources • DNA ligase connects the DNA pieces into continuous strands by forming bonds between adjacent nucleotides. Animation: Restriction Enzymes
    24. 24. Recognition sequence for a restriction enzyme Restriction enzyme Sticky end Sticky end DNA A restriction enzyme cuts the DNA into fragments. Figure 12.9-1
    25. 25. Recognition sequence for a restriction enzyme Restriction enzyme Sticky end Sticky end DNA A DNA fragment is added from another source. A restriction enzyme cuts the DNA into fragments. Figure 12.9-2
    26. 26. Recognition sequence for a restriction enzyme Restriction enzyme Sticky end Sticky end DNA A DNA fragment is added from another source. A restriction enzyme cuts the DNA into fragments. Fragments stick together by base pairing. Figure 12.9-3
    27. 27. Recognition sequence for a restriction enzyme Restriction enzyme Sticky end Sticky end DNA DNA ligase Recombinant DNA molecule A DNA fragment is added from another source. A restriction enzyme cuts the DNA into fragments. Fragments stick together by base pairing. DNA ligase joins the fragments into strands. Figure 12.9-4
    28. 28. Figure 12.12
    29. 29. © 2010 Pearson Education, Inc. DNA PROFILING AND FORENSIC SCIENCE • DNA profiling: – Can be used to determine if two samples of genetic material are from a particular individual – Has rapidly revolutionized the field of forensics, the scientific analysis of evidence from crime scenes • To produce a DNA profile, scientists compare genetic markers, sequences in the genome that vary from person to person. Video: Biotechnology Lab
    30. 30. DNA isolated Crime scene Suspect 1 Suspect 2 Figure 12.13-1
    31. 31. DNA isolated DNA amplified Crime scene Suspect 1 Suspect 2 Figure 12.13-2
    32. 32. DNA isolated DNA amplified DNA compared Crime scene Suspect 1 Suspect 2 Figure 12.13-3
    33. 33. © 2010 Pearson Education, Inc. Investigating Murder, Paternity etc. • DNA profiling can be used to: – Test the guilt of suspected criminals – Identify tissue samples of victims – Resolve paternity cases – Identify contraband animal products
    34. 34. DNA Profiling Techniques The Polymerase Chain Reaction (PCR) • The polymerase chain reaction (PCR): – Is a technique to copy quickly and precisely any segment of DNA and – Can generate enough DNA, from even minute amounts of blood or other tissue, to allow DNA profiling © 2010 Pearson Education, Inc.
    35. 35. Initial DNA segment Number of DNA molecules 1 2 4 8 Figure 12.15
    36. 36. © 2010 Pearson Education, Inc. Short Tandem Repeat (STR) Analysis • How do you test if two samples of DNA come from the same person? • Repetitive DNA: – Makes up much of the DNA that lies between genes in humans and – Consists of nucleotide sequences that are present in multiple copies in the genome
    37. 37. © 2010 Pearson Education, Inc. • Short tandem repeats (STRs) are: – Short sequences of DNA – Repeated many times, tandemly (one after another), in the genome • STR analysis: – Is a method of DNA profiling – Compares the lengths of STR sequences at certain sites in the genome Blast Animation: DNA Fingerprinting
    38. 38. Crime scene DNA Suspect’s DNA Same number of short tandem repeats Different numbers of short tandem repeats STR site 1 STR site 2 AGAT AGAT GATA GATA Figure 12.16
    39. 39. © 2010 Pearson Education, Inc. Gel Electrophoresis • STR analysis: – Compares the lengths of DNA fragments – Uses gel electrophoresis, a method for sorting macromolecules—usually proteins or nucleic acids—primarily by their – Electrical charge – Size Blast Animation: Gel Electrophoresis
    40. 40. Mixture of DNA fragments of different sizes Power source Gel Figure 12.17-1
    41. 41. Mixture of DNA fragments of different sizes Power source Gel Figure 12.17-2
    42. 42. Mixture of DNA fragments of different sizes Power source Gel Completed gel Band of longest (slowest) fragments Band of shortest (fastest) fragments Figure 12.17-3
    43. 43. © 2010 Pearson Education, Inc. • The DNA fragments are visualized as “bands” on the gel. • The differences in the locations of the bands reflect the different lengths of the DNA fragments.
    44. 44. Amplified crime scene DNA Amplified suspect’s DNA Longer fragments Shorter fragments Figure 12.18
    45. 45. © 2010 Pearson Education, Inc. GENOMICS AND PROTEOMICS • Genomics is the science of studying complete sets of genes (genomes). – The first targets of genomics were bacteria. – As of 2009, the genomes of nearly one thousand species have been published, including: – Mice – Fruit flies
    46. 46. Table 12.1
    47. 47. © 2010 Pearson Education, Inc. The Human Genome Project • Begun in 1990, the Human Genome Project was a massive scientific endeavor: – To determine the nucleotide sequence of all the DNA in the human genome and – To identify the location and sequence of every gene
    48. 48. © 2010 Pearson Education, Inc. • At the completion of the project in 2004: – Over 99% of the genome had been determined to 99.999% accuracy – 3.2 billion nucleotide pairs were identified – About 21,000 genes were found – About 98% of the human DNA was identified as noncoding
    49. 49. © 2010 Pearson Education, Inc. • The Human Genome Project can help map the genes for specific diseases such as: – Alzheimer’s disease – Parkinson’s disease
    50. 50. Figure 12.20
    51. 51. © 2010 Pearson Education, Inc. HUMAN GENE THERAPY • Human gene therapy: – Is a recombinant DNA procedure – Seeks to treat disease by altering the genes of the afflicted person – Often replaces or supplements the mutant version of a gene with a properly functioning one
    52. 52. Normal human gene isolated and cloned Healthy person Figure 12.24-1
    53. 53. Normal human gene isolated and cloned Normal human gene inserted into virus Healthy person Harmless virus (vector) Virus containing normal human gene Figure 12.24-2
    54. 54. Normal human gene isolated and cloned Normal human gene inserted into virus Virus injected into patient with abnormal gene Healthy person Harmless virus (vector) Virus containing normal human gene Bone marrow Bone of person with disease Figure 12.24-3
    55. 55. © 2010 Pearson Education, Inc. SAFETY AND ETHICAL ISSUES • As soon as scientists realized the power of DNA technology, they began to worry about potential dangers such as the: – Creation of hazardous new pathogens – Transfer of cancer genes into infectious bacteria and viruses
    56. 56. © 2010 Pearson Education, Inc. • Strict laboratory safety procedures have been designed to: – Protect researchers from infection by engineered microbes – Prevent microbes from accidentally leaving the laboratory
    57. 57. Figure 12.25
    58. 58. © 2010 Pearson Education, Inc. The Controversy over Genetically Modified Foods • GM strains account for a significant percentage of several agricultural crops in the United States.
    59. 59. Figure 12.26
    60. 60. © 2010 Pearson Education, Inc. • Advocates of a cautious approach are concerned that: – Crops carrying genes from other species might harm the environment – GM foods could be hazardous to human health – Transgenic plants might pass their genes to close relatives in nearby wild areas
    61. 61. © 2010 Pearson Education, Inc. • In 2000, negotiators from 130 countries (including the United States) agreed on a Biosafety Protocol that: – Requires exporters to identify GM organisms present in bulk food shipments
    62. 62. © 2010 Pearson Education, Inc. • In the United States, all projects are evaluated for potential risks by a number of regulatory agencies, including the: – Food and Drug Administration – Environmental Protection Agency – National Institutes of Health – Department of Agriculture
    63. 63. © 2010 Pearson Education, Inc. Ethical Questions Raised by DNA Technology • DNA technology raises legal and ethical questions—few of which have clear answers. – Should genetically engineered human growth hormone be used to stimulate growth in HGH-deficient children? – Do we have any right to alter an organism’s genes—or to create new organisms? – Should we try to eliminate genetic defects in our children and their descendants? – Should people use mail-in kits that can tell healthy people their relative risk of developing various diseases?
    64. 64. Figure 12.27
    65. 65. © 2010 Pearson Education, Inc. • DNA technologies raise many complex issues that have no easy answers. • We as a society and as individuals must become educated about DNA technologies to address the ethical questions raised by their use.
    66. 66. Evolution Connection: Profiling the Y Chromosome • Barring mutations, the human Y chromosome passes essentially intact from father to son. • By comparing Y DNA, researchers can learn about the ancestry of human males. © 2010 Pearson Education, Inc.
    67. 67. Crime scene Suspect 1 Suspect 2 DNA Polymerase chain reaction (PCR) amplifies STR sites Longer DNA fragments Shorter DNA fragments DNA fragments compared by gel electrophoresis Gel Figure 12.UN2
    68. 68. Normal human gene Virus Bone marrow Normal human gene is transcribed and translated in patient, potentially curing genetic disease permanently Figure 12.UN3

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