Chapter 12 DNA Technology and Genomics

Transcription

1 Chapter 12 DNA Technology and Genomics PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko

2 Introduction DNA technology has rapidly revolutionized the field of forensics, permits the use of gene cloning to produce medical and industrial products, allows for the development of genetically modified organisms for agriculture, permits the investigation of historical questions about human family and evolutionary relationships, and is invaluable in many areas of biological research Pearson Education, Inc.

3 Figure 12.0_1 Chapter 12: Big Ideas Gene Cloning Genetically Modified Organisms DNA Profiling Genomics

4 Figure 12.0_2

5 2012 Pearson Education, Inc. GENE CLONING

6 12.1 Genes can be cloned in recombinant plasmids Biotechnology is the manipulation of organisms or their components to make useful products. For thousands of years, humans have used microbes to make wine and cheese and selectively bred stock, dogs, and other animals. DNA technology is the set of modern techniques used to study and manipulate genetic material Pearson Education, Inc.

7 Figure 12.1A

8 12.1 Genes can be cloned in recombinant plasmids Genetic engineering involves manipulating genes for practical purposes. Gene cloning leads to the production of multiple, identical copies of a gene-carrying piece of DNA. Recombinant DNA is formed by joining nucleotide sequences from two different sources. One source contains the gene that will be cloned. Another source is a gene carrier, called a vector. Plasmids (small, circular DNA molecules independent of the bacterial chromosome) are often used as vectors Pearson Education, Inc.

9 12.1 Genes can be cloned in recombinant plasmids Steps in cloning a gene 1. Plasmid DNA is isolated. 2. DNA containing the gene of interest is isolated. 3. Plasmid DNA is treated with a restriction enzyme that cuts in one place, opening the circle. 4. DNA with the target gene is treated with the same enzyme and many fragments are produced. 5. Plasmid and target DNA are mixed and associate with each other Pearson Education, Inc.

10 12.1 Genes can be cloned in recombinant plasmids 6. Recombinant DNA molecules are produced when DNA ligase joins plasmid and target segments together. 7. The recombinant plasmid containing the target gene is taken up by a bacterial cell. 8. The bacterial cell reproduces to form a clone, a group of genetically identical cells descended from a single ancestral cell. Animation: Cloning a Gene 2012 Pearson Education, Inc.

11 Figure 12.1B E. coli bacterium Plasmid A cell with DNA containing the gene of interest Bacterial chromosome 1 A plasmid is isolated. 2 The cell s DNA is isolated. Gene of interest DNA 3 The plasmid is cut with an enzyme. Examples of gene use 4 The cell s DNA is cut with the same enzyme. Gene of interest 5 The targeted fragment and plasmid DNA are combined. Recombinant DNA plasmid 6 DNA ligase is added, which joins the two DNA molecules. Gene of interest Genes may be inserted into other organisms. Examples of protein use 7 The recombinant plasmid is taken up by a bacterium through transformation. 9 Recombinant bacterium 8 The bacterium reproduces. Harvested proteins may be used directly. Clone of cells

12 Figure 12.1B_s1 E. coli bacterium Plasmid A cell with DNA containing the gene of interest Bacterial chromosome 1 A plasmid is isolated. 2 The cell s DNA is isolated. Gene of interest DNA

13 Figure 12.1B_s2 E. coli bacterium Plasmid A cell with DNA containing the gene of interest Bacterial chromosome 1 A plasmid is isolated. 2 The cell s DNA is isolated. Gene of interest DNA 3 The plasmid is cut with an enzyme. 4 The cell s DNA is cut with the same enzyme. Gene of interest

14 Figure 12.1B_s3 E. coli bacterium Plasmid A cell with DNA containing the gene of interest Bacterial chromosome 1 A plasmid is isolated. 2 The cell s DNA is isolated. Gene of interest DNA 3 The plasmid is cut with an enzyme. 4 The cell s DNA is cut with the same enzyme. Gene of interest 5 The targeted fragment and plasmid DNA are combined.

15 Figure 12.1B_s4 E. coli bacterium Plasmid A cell with DNA containing the gene of interest Bacterial chromosome 1 A plasmid is isolated. 2 The cell s DNA is isolated. Gene of interest DNA 3 The plasmid is cut with an enzyme. 4 The cell s DNA is cut with the same enzyme. Gene of interest 5 The targeted fragment and plasmid DNA are combined. Recombinant DNA plasmid 6 DNA ligase is added, which joins the two DNA molecules. Gene of interest

16 Figure 12.1B_s5 Recombinant DNA plasmid Gene of interest 7 The recombinant plasmid is taken up by a bacterium through transformation. Recombinant bacterium

17 Figure 12.1B_s6 Recombinant DNA plasmid Gene of interest 7 The recombinant plasmid is taken up by a bacterium through transformation. Recombinant bacterium 8 The bacterium reproduces. Clone of cells

18 Figure 12.1B_s7 Genes may be inserted into other organisms. Recombinant DNA plasmid Gene of interest 7 The recombinant plasmid is taken up by a bacterium through transformation. 9 Recombinant bacterium 8 The bacterium reproduces. Harvested proteins may be used directly. Clone of cells

19 Figure 12.1B_8

20 Figure 12.1B_9

21 Figure 12.1B_10

22 Figure 12.1B_11

23 12.2 Enzymes are used to cut and paste DNA Restriction enzymes cut DNA at specific sequences. Each enzyme binds to DNA at a different restriction site. Many restriction enzymes make staggered cuts that produce restriction fragments with single-stranded ends called sticky ends. Fragments with complementary sticky ends can associate with each other, forming recombinant DNA. DNA ligase joins DNA fragments together. Animation: Restriction Enzymes 2012 Pearson Education, Inc.

24 Figure 12.2_s1 1 DNA A restriction enzyme cuts the DNA into fragments. Restriction enzyme recognition sequence Restriction enzyme 2 Sticky end Sticky end

25 Figure 12.2_s2 1 DNA A restriction enzyme cuts the DNA into fragments. Restriction enzyme recognition sequence Restriction enzyme 2 Sticky end A DNA fragment from another source is added. Sticky end 3 Gene of interest

26 Figure 12.2_s3 1 DNA A restriction enzyme cuts the DNA into fragments. Restriction enzyme recognition sequence Restriction enzyme 2 Sticky end A DNA fragment from another source is added. Sticky end 3 Gene of interest Two (or more) fragments stick together by base pairing. 4

27 Figure 12.2_s4 1 DNA A restriction enzyme cuts the DNA into fragments. Restriction enzyme recognition sequence Restriction enzyme 2 Sticky end A DNA fragment from another source is added. Sticky end 3 Gene of interest Two (or more) fragments stick together by base pairing. 4 DNA ligase pastes the strands together. DNA ligase 5 Recombinant DNA molecule

28 12.3 Cloned genes can be stored in genomic libraries A genomic library is a collection of all of the cloned DNA fragments from a target genome. Genomic libraries can be constructed with different types of vectors: plasmid library: genomic DNA is carried by plasmids, bacteriophage (phage) library: genomic DNA is incorporated into bacteriophage DNA, bacterial artificial chromosome (BAC) library: specialized plasmids that can carry large DNA sequences Pearson Education, Inc.

29 Figure 12.3 A genome is cut up with a restriction enzyme or Recombinant plasmid Recombinant phage DNA Bacterial clone Phage clone Plasmid library Phage library

30 12.4 Reverse transcriptase can help make genes for cloning Complementary DNA (cdna) can be used to clone eukaryotic genes. In this process, mrna from a specific cell type is the template. Reverse transcriptase produces a DNA strand from mrna. DNA polymerase produces the second DNA strand Pearson Education, Inc.

31 12.4 Reverse transcriptase can help make genes for cloning Advantages of cloning with cdna include the ability to study genes responsible for specialized characteristics of a particular cell type and obtain gene sequences that are smaller in size, easier to handle, and do not have introns Pearson Education, Inc.

32 Figure 12.4 CELL NUCLEUS DNA of a eukaryotic gene Exon Intron Exon Intron Exon 1 Transcription RNA transcript 2 RNA splicing (removes introns and joins exons) mrna TEST TUBE Reverse transcriptase cdna strand being synthesized cdna of gene (no introns) Direction of synthesis Isolation of mrna from the cell and the addition of reverse transcriptase; synthesis of a DNA strand Breakdown of RNA Synthesis of second DNA strand

33 Figure 12.4_1 CELL NUCLEUS DNA of a eukaryotic gene RNA transcript mrna Exon Intron Exon 1 2 Intron Exon Transcription RNA splicing (removes introns and joins exons)

34 Figure 12.4_2 TEST TUBE Reverse transcriptase 3 Isolation of mrna from the cell and the addition of reverse transcriptase; synthesis of a DNA strand cdna strand being synthesized cdna of gene (no introns) Direction of synthesis 4 5 Breakdown of RNA Synthesis of second DNA strand

35 12.5 Nucleic acid probes identify clones carrying specific genes Nucleic acid probes bind very selectively to cloned DNA. Probes can be DNA or RNA sequences complementary to a portion of the gene of interest. A probe binds to a gene of interest by base pairing. Probes are labeled with a radioactive isotope or fluorescent tag for detection Pearson Education, Inc.

36 12.5 Nucleic acid probes identify clones carrying specific genes One way to screen a gene library is as follows: 1. Bacterial clones are transferred to filter paper. 2. Cells are broken apart and the DNA is separated into single strands. 3. A probe solution is added and any bacterial colonies carrying the gene of interest will be tagged on the filter paper. 4. The clone carrying the gene of interest is grown for further study Pearson Education, Inc.

37 Figure 12.5 Radioactive nucleic acid probe (single-stranded DNA) The probe is mixed with single-stranded DNA from a genomic library. Single-stranded DNA Base pairing highlights the gene of interest.

38 GENETICALLY MODIFIED ORGANISMS 2012 Pearson Education, Inc.

39 12.6 Recombinant cells and organisms can mass-produce gene products Recombinant cells and organisms constructed by DNA technologies are used to manufacture many useful products, chiefly proteins. Bacteria are often the best organisms for manufacturing a protein product because bacteria have plasmids and phages available for use as genecloning vectors, can be grown rapidly and cheaply, can be engineered to produce large amounts of a particular protein, and often secrete the proteins directly into their growth medium Pearson Education, Inc.

40 12.6 Recombinant cells and organisms can mass-produce gene products Yeast cells are eukaryotes, have long been used to make bread and beer, can take up foreign DNA and integrate it into their genomes, have plasmids that can be used as gene vectors, and are often better than bacteria at synthesizing and secreting eukaryotic proteins Pearson Education, Inc.

41 12.6 Recombinant cells and organisms can mass-produce gene products Mammalian cells must be used to produce proteins with chains of sugars. Examples include human erythropoietin (EPO), which stimulates the production of red blood cells, factor VIII to treat hemophilia, and tissue plasminogen activator (TPA) used to treat heart attacks and strokes Pearson Education, Inc.

42 Table 12.6

43 Table 12.6_1

44 Table 12.6_2

45 12.6 Recombinant cells and organisms can mass-produce gene products Pharmaceutical researchers are currently exploring the mass production of gene products by whole animals or plants. Recombinant animals are difficult and costly to produce and must be cloned to produce more animals with the same traits Pearson Education, Inc.

46 Figure 12.6A

47 Figure 12.6A_1

48 Figure 12.6A_2

49 Figure 12.6B

50 12.7 CONNECTION: DNA technology has changed the pharmaceutical industry and medicine Products of DNA technology are already in use. Therapeutic hormones produced by DNA technology include insulin to treat diabetes and human growth hormone to treat dwarfism. DNA technology is used to test for inherited diseases, detect infectious agents such as HIV, and produce vaccines, harmless variants (mutants) or derivatives of a pathogen that stimulate the immune system Pearson Education, Inc.

51 Figure 12.7A

52 Figure 12.7B

53 12.8 CONNECTION: Genetically modified organisms are transforming agriculture Genetically modified (GM) organisms contain one or more genes introduced by artificial means. Transgenic organisms contain at least one gene from another species Pearson Education, Inc.

54 12.8 CONNECTION: Genetically modified organisms are transforming agriculture The most common vector used to introduce new genes into plant cells is a plasmid from the soil bacterium Agrobacterium tumefaciens and called the Ti plasmid Pearson Education, Inc.

55 Figure 12.8A_s1 Agrobacterium tumefaciens DNA containing the gene for a desired trait Ti plasmid 1 The gene is inserted into the plasmid. Recombinant Ti plasmid Restriction site

56 Figure 12.8A_s2 Agrobacterium tumefaciens DNA containing the gene for a desired trait Plant cell Ti plasmid Restriction site 1 The gene is inserted into the plasmid. Recombinant Ti plasmid 2 The recombinant plasmid is introduced into a plant cell. DNA carrying the new gene

57 Figure 12.8A_s3 Agrobacterium tumefaciens DNA containing the gene for a desired trait Plant cell Ti plasmid Restriction site 1 The gene is inserted into the plasmid. Recombinant Ti plasmid 2 The recombinant plasmid is introduced into a plant cell. DNA carrying the new gene 3 The plant cell grows into a plant. A plant with the new trait

58 12.8 CONNECTION: Genetically modified organisms are transforming agriculture GM plants are being produced that are more resistant to herbicides and pests and provide nutrients that help address malnutrition. GM animals are being produced with improved nutritional or other qualities Pearson Education, Inc.

59 Figure 12.8B

60 12.9 Genetically modified organisms raise concerns about human and environmental health Scientists use safety measures to guard against production and release of new pathogens. Concerns related to GM organisms include the potential introduction of allergens into the food supply and spread of genes to closely related organisms. Regulatory agencies are trying to address the safety of GM products, labeling of GM produced foods, and safe use of biotechnology Pearson Education, Inc.

61 Figure 12.9A

62 Figure 12.9B

63 12.10 CONNECTION: Gene therapy may someday help treat a variety of diseases Gene therapy aims to treat a disease by supplying a functional allele. One possible procedure is the following: 1. Clone the functional allele and insert it in a retroviral vector. 2. Use the virus to deliver the gene to an affected cell type from the patient, such as a bone marrow cell. 3. Viral DNA and the functional allele will insert into the patient s chromosome. 4. Return the cells to the patient for growth and division Pearson Education, Inc.

64 12.10 CONNECTION: Gene therapy may someday help treat a variety of diseases Gene therapy is an alteration of an afflicted individual s genes and attempt to treat disease. Gene therapy may be best used to treat disorders traceable to a single defective gene Pearson Education, Inc.

65 Figure Cloned gene (normal allele) 1 An RNA version of a normal human gene is inserted into a retrovirus. RNA genome of virus Retrovirus 2 Bone marrow cells are infected with the virus. 3 Viral DNA carrying the human gene inserts into the cell s chromosome. Bone marrow cell from the patient 4 The engineered cells are injected into the patient. Bone marrow

66 Figure 12.10_1 Cloned gene (normal allele) 1 An RNA version of a normal human gene is inserted into a retrovirus. RNA genome of virus Retrovirus

67 Figure 12.10_2 2 3 Bone marrow cells are infected with the virus. Viral DNA carrying the human gene inserts into the cell s chromosome. Bone marrow cell from the patient 4 The engineered cells are injected into the patient. Bone marrow

68 12.10 CONNECTION: Gene therapy may someday help treat a variety of diseases The first successful human gene therapy trial in 2000 tried to treat ten children with SCID (severe combined immune deficiency), helped nine of these patients, but caused leukemia in three of the patients, and resulted in one death Pearson Education, Inc.

69 12.10 CONNECTION: Gene therapy may someday help treat a variety of diseases The use of gene therapy raises many questions. How can we build in gene control mechanisms that make appropriate amounts of the product at the right time and place? How can gene insertion be performed without harming other cell functions? Will gene therapy lead to efforts to control the genetic makeup of human populations? Should we try to eliminate genetic defects in our children and descendants when genetic variety is a necessary ingredient for the survival of a species? 2012 Pearson Education, Inc.

70 2012 Pearson Education, Inc. DNA PROFILING

71 12.11 The analysis of genetic markers can produce a DNA profile DNA profiling is the analysis of DNA fragments to determine whether they come from the same individual. DNA profiling compares genetic markers from noncoding regions that show variation between individuals and involves amplifying (copying) of markers for analysis Pearson Education, Inc.

72 Figure DNA is isolated. Crime scene Suspect 1 Suspect 2 2 The DNA of selected markers is amplified. 3 The amplified DNA is compared.

73 12.12 The PCR method is used to amplify DNA sequences Polymerase chain reaction (PCR) is a method of amplifying a specific segment of a DNA molecule. PCR relies upon a pair of primers that are short, chemically synthesized, single-stranded DNA molecules, and complementary to sequences at each end of the target sequence. PCR is a three-step cycle that doubles the amount of DNA in each turn of the cycle Pearson Education, Inc.

74 Figure Cycle 1 yields two molecules Cycle 2 yields four molecules Cycle 3 yields eight molecules Target sequence Genomic DNA Heat separates DNA strands Primers bond with ends of target sequences. Primer DNA polymerase adds nucleotides New DNA 5

75 Figure 12.12_1 Cycle 1 yields two molecules Target sequence Genomic DNA Heat separates DNA strands. 2 5 Primers bond with ends of target sequences DNA polymerase adds nucleotides Primer New DNA

76 Figure 12.12_2 Cycle 2 yields four molecules Cycle 3 yields eight molecules

77 12.12 The PCR method is used to amplify DNA sequences The advantages of PCR include the ability to amplify DNA from a small sample, obtaining results rapidly, and a reaction that is highly sensitive, copying only the target sequence Pearson Education, Inc.

78 12.13 Gel electrophoresis sorts DNA molecules by size Gel electrophoresis can be used to separate DNA molecules based on size as follows: 1. A DNA sample is placed at one end of a porous gel. 2. Current is applied and DNA molecules move from the negative electrode toward the positive electrode. 3. Shorter DNA fragments move through the gel matrix more quickly and travel farther through the gel. 4. DNA fragments appear as bands, visualized through staining or detecting radioactivity or fluorescence. 5. Each band is a collection of DNA molecules of the same length. Video: Biotechnology Lab 2012 Pearson Education, Inc.

79 Figure A mixture of DNA fragments of different sizes Power source Gel Completed gel Longer (slower) molecules Shorter (faster) molecules

80 Figure 12.13_1 A mixture of DNA fragments of different sizes Power source Gel Completed gel Longer (slower) molecules Shorter (faster) molecules

81 Figure 12.13_2

82 12.14 STR analysis is commonly used for DNA profiling Repetitive DNA consists of nucleotide sequences that are present in multiple copies in the genome. Short tandem repeats (STRs) are short nucleotide sequences that are repeated in tandem, composed of different numbers of repeating units in individuals and used in DNA profiling. STR analysis compares the lengths of STR sequences at specific sites in the genome and typically analyzes 13 different STR sites Pearson Education, Inc.

83 Figure 12.14A STR site 1 STR site 2 Crime scene DNA The number of short tandem repeats match The number of short tandem repeats do not match Suspect s DNA

84 Figure 12.14B Crime scene DNA Suspect s DNA Longer STR fragments Shorter STR fragments

85 12.15 CONNECTION: DNA profiling has provided evidence in many forensic investigations DNA profiling is used to determine guilt or innocence in a crime, settle questions of paternity, identify victims of accidents, and probe the origin of nonhuman materials Pearson Education, Inc.

86 Figure 12.15A

87 Figure 12.15B

88 12.16 RFLPs can be used to detect differences in DNA sequences A single nucleotide polymorphism (SNP) is a variation at a single base pair within a genome. Restriction fragment length polymorphism (RFLP) is a change in the length of restriction fragments due to a SNP that alters a restriction site. RFLP analysis involves producing DNA fragments by restriction enzymes and sorting these fragments by gel electrophoresis Pearson Education, Inc.

89 Figure Restriction enzymes added DNA sample 1 DNA sample 2 w Cut z x y Cut y Cut Longer fragments Sample 1 x Sample 2 z Shorter fragments w y y

90 Figure 12.16_1 Restriction enzymes added DNA sample 1 DNA sample 2 w Cut z x y Cut y Cut

91 Figure 12.16_2 Longer fragments x Sample 1 Sample 2 z Shorter fragments w y y

92 2012 Pearson Education, Inc. GENOMICS

93 12.17 Genomics is the scientific study of whole genomes Genomics is the study of an organism s complete set of genes and their interactions. Initial studies focused on prokaryotic genomes. Many eukaryotic genomes have since been investigated Pearson Education, Inc.

94 Table 12.17

95 12.17 Genomics is the scientific study of whole genomes Genomics allows another way to examine evolutionary relationships. Genomic studies showed a 96% similarity in DNA sequences between chimpanzees and humans. Functions of human disease-causing genes have been determined by comparing human genes to similar genes in yeast Pearson Education, Inc.

96 12.18 CONNECTION: The Human Genome Project revealed that most of the human genome does not consist of genes The goals of the Human Genome Project (HGP) included determining the nucleotide sequence of all DNA in the human genome and identifying the location and sequence of every human gene Pearson Education, Inc.

97 12.18 CONNECTION: The Human Genome Project revealed that most of the human genome does not consist of genes Results of the Human Genome Project indicate that humans have about 20,000 genes in 3.2 billion nucleotide pairs, only 1.5% of the DNA codes for proteins, trnas, or rrnas, and the remaining 98.5% of the DNA is noncoding DNA including telomeres, stretches of noncoding DNA at the ends of chromosomes, and transposable elements, DNA segments that can move or be copied from one location to another within or between chromosomes Pearson Education, Inc.

98 Figure Exons (regions of genes coding for protein or giving rise to rrna or trna) (1.5%) Repetitive DNA that includes transposable elements and related sequences (44%) Introns and regulatory sequences (24%) Repetitive DNA unrelated to transposable elements (15%) Unique noncoding DNA (15%)

99 12.19 The whole-genome shotgun method of sequencing a genome can provide a wealth of data quickly The Human Genome Project proceeded through three stages that provided progressively more detailed views of the human genome. 1. A low-resolution linkage map was developed using RFLP analysis of 5,000 genetic markers. 2. A physical map was constructed from nucleotide distances between the linkage-map markers. 3. DNA sequences for the mapped fragments were determined Pearson Education, Inc.

100 12.19 The whole-genome shotgun method of sequencing a genome can provide a wealth of data quickly The whole-genome shotgun method was proposed in 1992 by molecular biologist J. Craig Venter, who used restriction enzymes to produce fragments that were cloned and sequenced in just one stage and ran high-performance computer analyses to assemble the sequence by aligning overlapping regions Pearson Education, Inc.

101 12.19 The whole-genome shotgun method of sequencing a genome can provide a wealth of data quickly Today, this whole-genome shotgun approach is the method of choice for genomic researchers because it is relatively fast and inexpensive. However, limitations of the whole-genome shotgun method suggest that a hybrid approach using genome shotgunning and physical maps may prove to be the most useful Pearson Education, Inc.

102 Figure Chromosome Chop up each chromosome with restriction enzymes DNA fragments Sequence the fragments Align the fragments Reassemble the full sequence

103 12.20 Proteomics is the scientific study of the full set of proteins encoded by a genome Proteomics is the study of the full protein sets encoded by genomes and investigates protein functions and interactions. The human proteome includes about 100,000 proteins. Genomics and proteomics are helping biologists study life from an increasingly holistic approach Pearson Education, Inc.

104 12.21 EVOLUTION CONNECTION: Genomes hold clues to human evolution Human and chimp genomes differ by 1.2% in single-base substitutions and 2.7% in insertions and deletions of larger DNA sequences. Genes showing rapid evolution in humans include genes for defense against malaria and tuberculosis, a gene regulating brain size, and the FOXP2 gene involved with speech and vocalization Pearson Education, Inc.

105 12.21 EVOLUTION CONNECTION: Genomes hold clues to human evolution Neanderthals were close human relatives, were a separate species, also had the FOXP2 gene, may have had pale skin and red hair, and were lactose intolerant Pearson Education, Inc.

106 Figure 12.21

107 You should now be able to 1. Explain how plasmids are used in gene cloning. 2. Explain how restriction enzymes are used to cut and paste DNA into plasmids. 3. Explain how plasmids, phages, and BACs are used to construct genomic libraries. 4. Explain how a cdna library is constructed and how it is different from genomic libraries constructed using plasmids or phages. 5. Explain how a nucleic acid probe can be used to identify a specific gene Pearson Education, Inc.

108 You should now be able to 6. Explain how different organisms are used to massproduce proteins of human interest. 7. Explain how DNA technology has helped to produce insulin, growth hormone, and vaccines. 8. Explain how genetically modified (GM) organisms are transforming agriculture. 9. Describe the risks posed by the creation and culturing of GM organisms and the safeguards that have been developed to minimize these risks Pearson Education, Inc.

109 You should now be able to 10. Describe the benefits and risks of gene therapy in humans. Discuss the ethical issues that these techniques present. 11. Describe the basic steps of DNA profiling. 12. Explain how PCR is used to amplify DNA sequences. 13. Explain how gel electrophoresis is used to sort DNA and proteins. 14. Explain how short tandem repeats are used in DNA profiling Pearson Education, Inc.

110 You should now be able to 15. Describe the diverse applications of DNA profiling. 16. Explain how restriction fragment analysis is used to detect differences in DNA sequences. 17. Explain why it is important to sequence the genomes of humans and other organisms. 18. Describe the structure and possible functions of the noncoding sections of the human genome. 19. Explain how the human genome was mapped Pearson Education, Inc.

111 You should now be able to 21. Compare the fields of genomics and proteomics. 22. Describe the significance of genomics to the study of evolutionary relationships and our understanding of the special characteristics of humans Pearson Education, Inc.

112 Figure 12.UN01 Cut Bacterium Bacterial clone DNA fragments Cut Plasmids Recombinant DNA plasmids Recombinant bacteria Genomic library

113 Figure 12.UN02 A mixture of DNA fragments A band is a collection of DNA fragments of one particular length Longer fragments move slower Shorter fragments move faster DNA is attracted to + pole due to PO 4 groups Power source

114 Figure 12.UN03 DNA amplified via (a) Bacterial plasmids DNA sample treated with treated with (b) DNA fragments sorted by size via (c) Recombinant plasmids are inserted into bacteria Add (d) Particular DNA sequence highlighted are copied via (e)

115 Figure 12.UN03_1 DNA amplified via (a) DNA sample Bacterial plasmids (b) treated with treated with

116 Figure 12.UN03_2 DNA fragments sorted by size via (c) Recombinant plasmids are inserted into bacteria (d) Add Particular DNA sequence highlighted are copied via (e)