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Frontiers of Genetics

Frontiers of Genetics. Honors Biology Chapter 13. Technology. DNA technology is a set of methods for studying and manipulating genetic material These techniques have brought about many remarkable scientific advances Genetically modified food DNA fingerprinting The Human Genome Project.

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Frontiers of Genetics

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  1. Frontiers of Genetics Honors Biology Chapter 13

  2. Technology • DNA technology is a set of methods for studying and manipulating genetic material • These techniques have brought about many remarkable scientific advances • Genetically modified food • DNA fingerprinting • The Human Genome Project

  3. RECOMBINANT DNA TECHNOLOGY • Recombinant DNA technology is a set of techniques for combining genes from different sources into a single DNA molecule • An organism that carries recombinant DNA is called a genetically modified (GM) organism • Recombinant DNA technology is applied in the field of biotechnology • Biotechnology uses various organisms to perform practical tasks

  4. Cell containing geneof interest Host cell 1 DNA Recombinant DNA(host DNA plusgene of interest) 2 Gene ofinterest Cell multiplies andproduces protein 3 Genes may be insertedinto another organism Protein may be harvested OR Gene for pest resistanceinserted into plants Protein dissolves blood clotsin heart attack therapy Figure 12.2

  5. Using Plasmids • Plasmid is small circle of bacterial DNA • Foreign DNA can be inserted into plasmid • Forms recombinant plasmids • Plasmid is a cloning vector • Can deliver DNA into another cell

  6. Using Plasmids DNA fragments + enzymes recombinant plasmids host cells containing recombinant plasmids

  7. Genetic Modification • By transferring the gene for a desired protein product into a bacterium, proteins can be produced in large quantities • In 1982 Humulin, human insulin, was produced by genetically modified bacteria

  8. DNA technology is also helping medical researchers develop vaccines • A vaccine is a harmless variant or derivative of a pathogen • Vaccines are used to prevent infectious diseases Figure 12.4

  9. Isolate DNAfrom twosources 1 Bacterial cell Human cell • Recombinant DNA techniques can help biologists produce large quantities of a desired protein DNA Cut bothDNAs 2 Plasmid DNAfragments Gene V Othergenes Gene V Mix the DNAs and join them together 3 Recombinant DNA plasmids Bacteria take up recombinant plasmids 4 Recombinant bacteria Clone the bacteria 5 Bacterial clones Find the clone with gene V 6 Grow bacteria and isolate protein V 7 Protein V Figure 12.9

  10. DNA Recombination • 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 “pasted” into a plasmid

  11. Recognition sequence for a restriction enzyme 1 Restriction enzymecuts DNA intofragments Sticky end Sticky end 2 Addition of a DNAfragment fromanother source 3 Fragments sticktogether bybase pairing 4 DNA ligasejoins the strands Recombinant DNA molecule Figure 12.10

  12. How a DNA probe tags a gene Radioactive probe (DNA) Mix with single-stranded DNA from various bacterial clones Single-stranded DNA Base pairing indicatesthe gene of interest Figure 12.11

  13. Genetically Modified (GM) Foods • Today, DNA technology is quickly replacing traditional plant-breeding programs • In 2002, roughly half of the American crops of soybeans and corn were genetically modified in some way Figure 12.5a

  14. Corn has been genetically modified to resist insect infestation • This corn has been damaged by the European corn borer Figure 12.5b

  15. “Golden rice” has been genetically modified to contain beta-carotene • Our bodies use beta-carotene to make vitamin A Figure 12.6

  16. Farm Animals and “Pharm” Animals • While transgenic plants are used today as commercial products, transgenic whole animals are currently only in the testing phase • These transgenic sheep carry a gene for a human blood protein • This protein may help in the treatment of cystic fibrosis Figure 12.7

  17. While transgenic animals are currently used to produce potentially useful proteins, none are yet found in our food supply • It is possible that DNA technology will eventually replace traditional animal breeding

  18. Ethical Issues • Who decides what should be “corrected” through genetic engineering? • Should animals be modified to provide organs for human transplants? • Should humans be cloned?

  19. DNA FINGERPRINTING • DNA technology has rapidly revolutionized the field of forensics • Forensics is the scientific analysis of evidence from crime scenes • DNA fingerprinting can be used to determine whether or not two samples of genetic material are from the same individual

  20. Crime scene Suspect 1 Suspect 2 DNA collected 1 DNA amplified if necessary 2 DNA cut into fragments 3 DNA fragmentscompared 4 Figure 12.13

  21. Gel Electrophoresis • The first step of RFLP analysis is to cut up a sample of DNA with a restriction enzyme • This creates a mixture of restriction fragments • The next step is to determine the number and size of fragments InitialDNAsegment

  22. Blood on defendant’sclothes Defendant’sblood Victim’sblood • DNA fingerprints from a murder case Figure 12.19

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