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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.1 Biotechnology Chapter 20.

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1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.1 Biotechnology Chapter 20

2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The DNA Toolbox Sequencing of the genomes of more than 7,000 species was under way in 2010 Recombinant DNA nucleotide sequences from two different sources combined in vitro into the same DNA molecule © 2011 Pearson Education, Inc.

3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genetic engineering direct manipulation of genes for practical purposes Biotechnology manipulation of organisms or their genetic components to make useful products © 2011 Pearson Education, Inc.

4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Foreign DNA inserted into plasmid* plasmid inserted into bacterial cell Reproduction in bacterial cell cloning of plasmid with foreign DNA multiple copies of a single gene *Plasmids are small circular DNA molecules that replicate separately from the bacterial chromosome © 2011 Pearson Education, Inc. DNA Cloning

5 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.2 Bacterium Bacterial chromosome Plasmid 2134 Gene inserted into plasmid Cell containing gene of interest Recombinant DNA (plasmid) Gene of interest Plasmid put into bacterial cell DNA of chromosome (foreign DNA) Recombinant bacterium Host cell grown in culture to form a clone of cells containing the cloned gene of interest Gene of interest Protein expressed from gene of interest Protein harvested Copies of gene Basic research and various applications Basic research on protein Basic research on gene Gene for pest resistance inserted into plants Gene used to alter bacteria for cleaning up toxic waste Protein dissolves blood clots in heart attack therapy Human growth hormone treats stunted growth

6 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Using Restriction Enzymes to Make Recombinant DNA Bacterial restriction enzymes cut DNA molecules at specific DNA sequences called restriction sites Yields restriction fragments Most useful restriction enzymes give staggered cut sticky ends. © 2011 Pearson Education, Inc. Animation: Restriction Enzymes

7 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sticky ends bond with complementary sticky ends of other fragments DNA ligase seals bonds between fragments © 2011 Pearson Education, Inc.

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G

9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure One possible combination DNA fragment added from another molecule cut by same enzyme. Base pairing occurs. Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G G G CTTAA G G G G AATT C C TTAA

10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Recombinant DNA molecule One possible combination DNA ligase seals strands DNA fragment added from another molecule cut by same enzyme. Base pairing occurs. Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G G G CTTAA G G G G AATT C C TTAA

11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cloning a Eukaryotic Gene in a Bacterial Plasmid A cloning vector (original plasmid) DNA molecule that carries foreign DNA into a host cell © 2011 Pearson Education, Inc.

12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.4 Bacterial plasmid TECHNIQUE RESULTS amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid Bacteria carrying plasmids Colony carrying non- recombinant plasmid with intact lacZ gene Colony carrying recombinant plasmid with disrupted lacZ gene One of many bacterial clones

13 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.4a-1 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments

14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.4a-2 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid

15 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.4a-3 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid Bacteria carrying plasmids

16 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.4b RESULTS Bacteria carrying plasmids Colony carrying non- recombinant plasmid with intact lacZ gene Colony carrying recombinant plasmid with disrupted lacZ gene One of many bacterial clones

17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Storing Cloned Genes in DNA Libraries A genomic library is made using plasmids or bacteriophages © 2011 Pearson Education, Inc.

18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.5 Foreign genome Cut with restriction enzymes into either small fragments large fragments or Recombinant plasmids Plasmid clone (a) Plasmid library (b) BAC clone Bacterial artificial chromosome (BAC) Large insert with many genes (c) Storing genome libraries

19 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Made by cloning DNA made in vitro by reverse transcription of all the mRNA produced by a particular cell A cDNA library represents only the subset of genes transcribed into mRNA in the original cells © 2011 Pearson Education, Inc. Complementary DNA (cDNA) library

20 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA in nucleus mRNAs in cytoplasm

21 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA in nucleus mRNAs in cytoplasm mRNA Reverse transcriptase Poly-A tail DNA strand Primer A A A T T T T T

22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA in nucleus mRNAs in cytoplasm mRNA Reverse transcriptase Poly-A tail DNA strand Primer A A A T T T T T

23 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA in nucleus mRNAs in cytoplasm mRNA Reverse transcriptase Poly-A tail DNA strand Primer DNA polymerase A A A T T T T T

24 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA in nucleus mRNAs in cytoplasm mRNA Reverse transcriptase Poly-A tail DNA strand Primer DNA polymerase cDNA A A A T T T T T

25 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Screening a Library for Clones Carrying a Gene of Interest Identified with a nucleic acid probe having a sequence complementary to the gene Process is called nucleic acid hybridization © 2011 Pearson Education, Inc.

26 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A probe can be synthesized that is complementary to the gene of interest For example, if the desired gene is – Then we would synthesize this probe © 2011 Pearson Education, Inc. 5 3 CTCAT CACCGGC 5 3 G A G T A G T G G C C GG A G T A G T G G C C G

27 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.7 Radioactively labeled probe molecules Gene of interest Probe DNA Single- stranded DNA from cell Film Location of DNA with the complementary sequence Nylon membrane Multiwell plates holding library clones TECHNIQUE GAGTAGTGGCCG CTCATCACCGGC

28 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic Cloning and Expression Systems Avoid eukaryote-bacterial incompatibility issues by using eukaryotic cells, such as yeasts or cultured mammal cells, as hosts for cloning and expressing genes © 2011 Pearson Education, Inc.

29 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Electroporation: applying a brief electrical pulse to create temporary holes in plasma membranes introduces recombinant DNA into eukaryotic cells Alternatively, scientists can inject DNA into cells using microscopically thin needles © 2011 Pearson Education, Inc.

30 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cross-Species Gene Expression and Evolutionary Ancestry The remarkable ability of bacteria to express some eukaryotic proteins underscores the shared evolutionary ancestry of living species e.g., Pax-6 (gene that directs formation of vertebrate eye); also directs the formation of insect eye © 2011 Pearson Education, Inc.

31 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Amplifying DNA in Vitro: The Polymerase Chain Reaction (PCR) Polymerase chain reaction, PCR produce many copies of a specific target segment of DNA Key to PCR is an unusual, heat-stable DNA polymerase called Taq polymerase. © 2011 Pearson Education, Inc.

32 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.8 Genomic DNA Target sequence Denaturation Annealing Extension Primers New nucleotides Cycle 1 yields 2 molecules Cycle 2 yields 4 molecules Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence TECHNIQUE

33 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.8a Genomic DNA Target sequence TECHNIQUE

34 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Denaturation Annealing Extension Primers New nucleo- tides Cycle 1 yields 2 molecules Figure 20.8b

35 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.8c Cycle 2 yields 4 molecules

36 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.8d Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence

37 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gel Electrophoresis and Southern Blotting Gel electrophoresis method of rapidly analyzing and comparing genomes Uses a gel as a molecular sieve to separate nucleic acids or proteins by size, electrical charge, and other properties © 2011 Pearson Education, Inc. Animation: Biotechnology Lab

38 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.9 Mixture of DNA mol- ecules of different sizes Power source Longer molecules Cathode Anode Wells Gel Shorter molecules TECHNIQUE RESULTS 1 2

39 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.9a Mixture of DNA mol- ecules of different sizes Power source Longer molecules Cathode Anode Wells Gel Shorter molecules TECHNIQUE 2 1

40 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.9b RESULTS

41 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Restriction fragment analysis DNA fragments produced by restriction enzyme digestion sorted by gel electrophoresis © 2011 Pearson Education, Inc.

42 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Variations in DNA sequence are called polymorphisms Sequence changes that alter restriction sites are called RFLPs (restriction fragment length polymorphisms) © 2011 Pearson Education, Inc.

43 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Normal -globin allele Sickle-cell mutant -globin allele Large fragment Normal allele Sickle-cell allele 201 bp 175 bp 376 bp (a) Dde I restriction sites in normal and sickle-cell alleles of the -globin gene (b) Electrophoresis of restriction fragments from normal and sickle-cell alleles 201 bp 175 bp 376 bp Large fragment Dde I

44 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.10a Normal -globin allele Sickle-cell mutant -globin allele (a) Dde I restriction sites in normal and sickle-cell alleles of the -globin gene 201 bp 175 bp 376 bp Large fragment Dde I

45 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.10b Large fragment Normal allele Sickle-cell allele 201 bp 175 bp 376 bp (b) Electrophoresis of restriction fragments from normal and sickle-cell alleles

46 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Southern blotting combines gel electrophoresis of DNA fragments with nucleic acid hybridization © 2011 Pearson Education, Inc.

47 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA restriction enzyme TECHNIQUE I Normal -globin allele II Sickle-cell allele III Heterozygote Restriction fragments Nitrocellulose membrane (blot) Heavy weight Gel Sponge Alkaline solution Paper towels II IIII II IIII II IIII Preparation of restriction fragments Gel electrophoresis DNA transfer (blotting) Radioactively labeled probe for -globin gene Nitrocellulose blot Probe base-pairs with fragments Fragment from sickle-cell -globin allele Fragment from normal - globin allele Film over blot Hybridization with labeled probe Probe detection 5

48 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings DNA Sequencing Relatively short DNA fragments can be sequenced by the dideoxy chain termination method, the first automated method to be employed Modified nucleotides called dideoxyribonucleotides (ddNTP) attach to synthesized DNA strands of different lengths Each type of ddNTP is tagged with a distinct fluorescent label that identifies the nucleotide at the end of each DNA fragment The DNA sequence can be read from the resulting spectrogram © 2011 Pearson Education, Inc.

49 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA (template strand) TECHNIQUE 5 3 C C C C T T T G G A A A A G T T T DNA polymerase Primer 5 3 P P P OH G dATP dCTP dTTP dGTP Deoxyribonucleotides Dideoxyribonucleotides (fluorescently tagged) P P P H G ddATP ddCTP ddTTP ddGTP 5 3 C C C C T T T G G A A A A DNA (template strand) Labeled strands ShortestLongest 5 3 ddC ddG ddA ddG ddT ddC G T T T G T T T C G T T T C T T G G T T T C T G A G T T T C T G A A G T T T C T G A A G G T T T C T G A A G T G T T T C T G A A G T C G T T T C T G A A G T C A Direction of movement of strands Longest labeled strand Detector Laser Shortest labeled strand RESULTS Last nucleotide of longest labeled strand Last nucleotide of shortest labeled strand G G G A A A C C T

50 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.12a DNA (template strand) TECHNIQUE Primer Deoxyribonucleotides Dideoxyribonucleotides (fluorescently tagged) DNA polymerase OH H G G dATP dCTP dTTP dGTP P P P P P P ddATP ddCTP ddTTP ddGTP T T T G G G C C C C T T T A A A A

51 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.12b DNA (template strand) Labeled strands ShortestLongest Direction of movement of strands Longest labeled strand Detector Laser Shortest labeled strand TECHNIQUE (continued) 5 3 G G C C C C T T T A A A A T T T G ddC ddG ddA ddT 3 5 T T T G C T T T G C G T T T G C G A T T T G C G A A T T T G C G A A G T T T C G A A G T T T T C G A A G T C A T T T C G A A G T C G GG

52 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.12c RESULTS Last nucleotide of longest labeled strand Last nucleotide of shortest labeled strand G G G A A A C C T Direction of movement of strands Longest labeled strand Detector Laser Shortest labeled strand

53 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Reverse transcriptase-polymerase chain reaction (RT-PCR) Reverse transcriptase + mRNA cDNA, which serves as a template for PCR amplification of the gene of interest © 2011 Pearson Education, Inc.

54 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure cDNA synthesis PCR amplification Gel electrophoresis mRNAs cDNAs Primers -globin gene Embryonic stages RESULTS TECHNIQUE

55 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Expression of Interacting Groups of Genes DNA microarray assays compare patterns of gene expression in different tissues, at different times, or under different conditions © 2011 Pearson Education, Inc.

56 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Isolate mRNA TECHNIQUE Make cDNA by reverse transcription, using fluorescently labeled nucleotides. Apply the cDNA mixture to a microarray, a different gene in each spot. The cDNA hybridizes with any complementary DNA on the microarray. Rinse off excess cDNA; scan microarray for fluorescence. Each fluorescent spot (yellow) represents a gene expressed in the tissue sample. Tissue sample mRNA molecules Labeled cDNA molecules (single strands) DNA fragments representing a specific gene DNA microarray DNA microarray with 2,400 human genes Figure 20.15

57 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.15a DNA microarray with 2,400 human genes

58 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Determining Gene Function in vitro mutagenesis mutations are introduced into a cloned gene, altering or destroying its function Mutated gene returned to the cell normal gene function determined by examining the mutants phenotype Gene expression can also be silenced using RNA interference (RNAi) © 2011 Pearson Education, Inc.

59 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genetic markers called SNPs (single nucleotide polymorphisms) occur on average every 100– 300 base pairs SNPs can be detected by PCR, and any SNP shared by people affected with a disorder but not among unaffected people may pinpoint the location of the disease-causing gene © 2011 Pearson Education, Inc.

60 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure DNA SNP Normal allele Disease-causing allele T C

61 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organismal cloning produces one or more organisms genetically identical to the parent that donated the single cell Cloning © 2011 Pearson Education, Inc.

62 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cloning Plants: Single-Cell Cultures Totipotent cell can generate a complete new organism Plant cloning is used extensively in agriculture © 2011 Pearson Education, Inc.

63 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Cross section of carrot root 2-mg fragments Fragments were cultured in nu- trient medium; stirring caused single cells to shear off into the liquid. Single cells free in suspension began to divide. Embryonic plant developed from a cultured single cell. Plantlet was cultured on agar medium. Later it was planted in soil. Adult plant

64 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cloning Animals: Nuclear Transplantation Nucleus of an unfertilized egg cell is replaced with the nucleus of a differentiated cell © 2011 Pearson Education, Inc.

65 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Frog embryo Frog egg cellFrog tadpole UV Less differ- entiated cell Donor nucleus trans- planted Enucleated egg cell Fully differ- entiated (intestinal) cell Donor nucleus trans- planted Egg with donor nucleus activated to begin development Most develop into tadpoles. Most stop developing before tadpole stage. EXPERIMENT RESULTS Figure 20.18

66 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Reproductive Cloning of Mammals 1997, Scottish researchers announced the birth of Dolly, a lamb cloned from an adult sheep by nuclear transplantation from a differentiated mammary cell © 2011 Pearson Education, Inc.

67 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Mammary cell donor TECHNIQUE RESULTS Cultured mammary cells Egg cell from ovary Egg cell donor Nucleus removed Cells fused Grown in culture Implanted in uterus of a third sheep Embryonic development Nucleus from mammary cell Early embryo Surrogate mother Lamb (Dolly) genetically identical to mammary cell donor

68 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.19a Mammary cell donor 213 TECHNIQUE Cultured mammary cells Egg cell from ovary Egg cell donor Nucleus removed Cells fused Nucleus from mammary cell

69 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 456 RESULTS Grown in culture Implanted in uterus of a third sheep Embryonic development Nucleus from mammary cell Early embryo Surrogate mother Lamb (Dolly) genetically identical to mammary cell donor Figure 20.19b

70 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Since 1997, cloning has been demonstrated in many mammals, including mice, cats, cows, horses, mules, pigs, and dogs CC (for Carbon Copy) was the first cat cloned; however, CC differed somewhat from her female parent Cloned animals do not always look or behave exactly the same © 2011 Pearson Education, Inc.

71 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.20

72 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Stem Cells of Animals Relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types Stem cells isolated from early embryos at the blastocyst stage are called embryonic stem (ES) cells; these are able to differentiate into all cell types The adult body also has stem cells, which replace nonreproducing specialized cells © 2011 Pearson Education, Inc.

73 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Cultured stem cells Different culture conditions Different types of differentiated cells Embryonic stem cells Adult stem cells Cells generating all embryonic cell types Cells generating some cell types Liver cells Nerve cells Blood cells

74 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Practical applications of DNA technology © 2011 Pearson Education, Inc.

75 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Medical Applications Identification of human genes in which mutation plays a role in genetic diseases © 2011 Pearson Education, Inc.

76 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Diagnosis and Treatment of Diseases Can diagnose PCR and sequence-specific primers, then sequencing the amplified product to look for the disease-causing mutation SNPs may be associated with a disease-causing mutation © 2011 Pearson Education, Inc.

77 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Human Gene Therapy The alteration of an afflicted individuals genes © 2011 Pearson Education, Inc.

78 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Cloned gene Retrovirus capsid Bone marrow cell from patient Viral RNA Bone marrow Insert RNA version of normal allele into retrovirus. Let retrovirus infect bone marrow cells that have been removed from the patient and cultured. Viral DNA carrying the normal allele inserts into chromosome. Inject engineered cells into patient.

79 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Pharmaceutical Products Advances in DNA technology and genetic research are important to the development of new drugs to treat diseases © 2011 Pearson Education, Inc.

80 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Transgenic animals are made by introducing genes from one species into the genome of another animal pharmaceutical factories Protein Production by Pharm Animals © 2011 Pearson Education, Inc.

81 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 20.24

82 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Forensic Evidence and Genetic Profiles An individuals unique DNA sequence, or genetic profile, can be obtained by analysis of tissue or body fluids Can use PCR and/ or Southern Blotting/ RFLP © 2011 Pearson Education, Inc.

83 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure This photo shows Washington just before his release in 2001, after 17 years in prison. (a) (b) These and other STR data exonerated Washington and led Tinsley to plead guilty to the murder. Semen on victim Earl Washington Kenneth Tinsley 17,19 16,18 17,19 13,16 14,15 13,16 12,12 11,12 12,12 Source of sample STR marker 1 STR marker 2 STR marker 3

84 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Environmental Cleanup Modified microorganisms can be used to extract minerals from the environment or degrade potentially toxic waste materials © 2011 Pearson Education, Inc.

85 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Agricultural Applications DNA technology is being used to improve agricultural productivity and food quality Genetic engineering of transgenic animals speeds up the selective breeding process Beneficial genes can be transferred between varieties of species © 2011 Pearson Education, Inc.

86 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Ti plasmid is the most commonly used vector for introducing new genes into plant cells Genetic engineering in plants has been used to transfer many useful genes including those for herbicide resistance, increased resistance to pests, increased resistance to salinity, and improved nutritional value of crops © 2011 Pearson Education, Inc.

87 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Plant with new trait RESULTS TECHNIQUE Ti plasmid Site where restriction enzyme cuts DNA with the gene of interest Recombinant Ti plasmid T DNA Agrobacterium tumefaciens

88 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Safety and Ethical Questions Raised by DNA Technology Potential benefits of genetic engineering must be weighed against potential hazards of creating harmful products or procedures Guidelines are in place in the United States and other countries to ensure safe practices for recombinant DNA technology © 2011 Pearson Education, Inc.

89 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genetically modified (GM) organisms © 2011 Pearson Education, Inc.


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