Chapter 13 Genetic Engineering

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Chapter 13Genetic Engineering
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Glow in the Dark, oil eating bacteria clones
hybridssay what??

• Yes, these things are real and possible.
• If you could manipulate DNA, what would you do?
• What application would it have for society as a
  whole?
• What are some of the moral questions that might
  arise from your proposed manipulation?

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Changing the Living World

• 1. Selective Breeding 
• Selective breeding? allowing only the organisms
  with desired traits to breed
• Takes advantage of naturally occurring variation
• Ex domestic dogs, cats, farm animals, most crops

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Cont. Selective Breeding

• Hybridization? crossing dissimilar individuals
  bringing together the best of both organisms
• Hybrids usually hardier than either of the
  parents
• Ex crossing disease resistance with food
  production
• Inbreeding? continued breeding of individuals
  with similar characteristics
• Increased risk of genetic defects
• Ex maintaining characteristics in breeds of dogs

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• Ever wondered what a
• human-dog hybrid
• would look like?!?!

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Human-Dog hybrid was a sculpture created by an
Australian artist named Patricia Piccinini.
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Increasing Variation

• Breeders increase variation by inducing mutations
  ( ultimate source of variation) 
• New kinds of bacteria produced by treating them
  with chemicals and radiation
• - Results bacteria that can digest oil used
  to clean up oil spills

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Cont. Increasing Variation

• New kinds of plants produced by treating them
  with drugs that prevent chromosome separation
  during meiosis
• - Results polyploidy cells? plants larger
  and stronger (LETHAL in animals!)

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Manipulating DNA

• Genetic engineering? making changes in the DNA
  code of an organism
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• 1. The Tools of Molecular Biology
• a. DNA extraction? open cells and separate DNA
  from other cell parts
• b. Cutting DNA via restriction enzymes? cut DNA
  into smaller pieces at a specific sequence of
  nucleotides
• c. Separating DNA via gel electrophoresis?
  mixture of DNA fragments are put in one end of
  porous gel and an electric voltage is applied
• - DNA is negatively charged so the fragments
  begin to travel toward the positive end of the
  gel
• - The smaller the fragment, the faster it
  travels the larger/slower

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Cutting DNA


Recombinant DNA is DNA taken from two different sources and fused into a single DNA molecule. Special DNA cutting enzymes, called restriction enzymes, cut the DNA at specific sites. Each restriction enzyme recognizes a different nucleotide sequence. DNA that is cut with a restriction enzyme will have single-stranded ends, called sticky ends. Two molecules of DNA cut with the same restriction enzyme will have the same exposed nucleotides and will undergo complementary base pairing.
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Gel Electropheresis
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Electrophoresis
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Cont. Manipulating DNA

• 2. Using the DNA Sequence 
• a. Reading the sequence? use fluorescent dyes to
  identify specific bases and DNA sequences
• b. Cutting and pasting via recombinant DNA? use
  restriction enzymes to cut a gene form one
  organism and using special enzymes (ligase)
  paste it into the DNA of another organism
• c. Making copies via polymerase chain reaction
  (PCR)? produces multiple copies of DNA strand

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Cell Transformation

• 1. Transformation? process in which bacteria
  or some other organism takes in DNA from its
  environment and incorporates it into its own DNA
•   a. Transforming Bacteria
• Plasmids? small circular pieces of DNA useful
  for DNA transfer for 2 reasons
• 1. Bacterial origin of replication
• 2. Genetic marker? a gene that makes it
  possible to identify the transformed bacteria
• Ex genes for resistance to antibiotics

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Cont. Transformation

• b. Transforming Plant Cells
• Infect plant cells with recombinant plasmid whose
  tumor producing gene has been inactivated
• c. Transforming Animal Cells
• Inject DNA directly into the nucleus of an egg
  cell, foreign DNA is inserted into the chromosome

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Applications of Genetic Engineering

•  1. Transgenic Organisms? contain genes from
  other organisms
• a. Transgenic Microorganisms
• Bacteria transformed with human genes for
  insulin, growth hormone, clotting favors etc.
  produce human products
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• b. Transgenic Animals
• Mice with human immune systems are used to study
  effects of disease
• Livestock with extra copies of growth hormone to
  produce faster growth and less fatty meat
• c. Transgenic Plants
• Genetically modified food (GM)? 52 of soy beans
  and 25 corn
• Plants contain genes that produce natural
  insecticide or weed resistance

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Transgenic Animal Belgian Blue Cattle
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Cloning

• 1. Clone? member of a population of genetically
  identical cells produced from a single cell  
• Steps
• 1. Nucleus of egg cell removed
• 2. Donor nucleus fused with egg cell using an
  electric shock
• 3. Fused cell begins to divide
• 4. Embryo placed in uterus of foster mother

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Dollys Bonnie