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Genetic engineering and biotechnology


Title: Genetic engineering and biotechnology Created Date: 1/28/2009 4:11:17 AM Document presentation format: On-screen Show Company: Nellie's Dungeon – PowerPoint PPT presentation

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Title: Genetic engineering and biotechnology

Genetic engineering and biotechnology
  • Topic 4.4

Assessment statements
  • 4.4.1 Outline the use of polymerase chain
    reaction (PCR) to copy and amplify minute
    quantities of DNA.
  • 4.4.2 State that, in gel electrophoresis,
    fragments of DNA move in an electric field and
    are separated according to their size.
  • 4.4.3 State that gel electrophoresis of DNA is
    used in DNA profiling.
  • 4.4.4 Describe the application of DNA profiling
    to determine paternity and also in forensic
  • 4.4.5 Analyse DNA profiles to draw conclusions
    about paternity or forensic investigations.
  • 4.4.6 Outline three outcomes of the sequencing of
    the complete human genome.
  • 4.4.7 State that, when genes are transferred
    between species, the amino acid sequence of
    polypeptides translated from them is unchanged
    because the genetic code is universal.
  • 4.4.8 Outline a basic technique used for gene
    transfer involving plasmids, a host cell
    (bacterium, yeast or other cell), restriction
    enzymes (endonucleases) and DNA ligase.
  • 4.4.9 State two examples of the current uses of
    genetically modified crops or animals.
  • 4.4.10 Discuss the potential benefits and
    possible harmful effects of one example of
    genetic modification.
  • 4.4.11 Define clone.
  • 4.4.12 Outline a technique for cloning using
    differentiated animal cells.
  • 4.4.13 Discuss the ethical issues of therapeutic
    cloning in humans.

Polymerase chain reaction (PCR)
  • Laboratory technique which takes a very small
    quantity of DNA and copies all the nucleic acids
    in it to make millions of copies of the DNA
  • Way to ensure that enough DNA for analysis can be

Gel electrophoresis
  • Laboratory technique used to separate fragments
    of DNA in an effort to identify its origin
  • Enzymes used to chop up DNA strands into
  • Fragments are placed into small wells in the gel
  • Gel is exposed to an electric current
  • Heaviest, largest and least charged particles do
    not move easily through the gel
  • Smallest, least massive and most charged
    particles pass through the gel to the other side
  • Intermediate particles are distributed in between
  • In the end, the fragments leave a banded pattern
    of DNA

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DNA profiling
  • Process of matching an unknown sample of DNA with
    a known sample to see if they correspond
  • Referred to as DNA fingerprinting
  • If, after separation by gel electrophoresis, the
    pattern of bands formed by two samples of DNA
    fragments are identical, it means that both came
    from the same individual
  • If the patterns are similar, it means that the
    two individuals are most probably related

Applications of DNA profiling
  • Paternity
  • Match suspects
  • Studies of ecosystems
  • Social relationships
  • Migrating patterns
  • Nesting habits
  • Credibility to evolution

  • How would you feel if you were to find out from
    DNA profiling that your father was not your
    biological father?
  • What effect would such a result have on the
    relationships between siblings or between
  • What kind of emotions might someone feel after
    spending 18 years in prison, and then being freed
    thanks to a DNA test?

The Human Genome Project
  • 1990 2003
  • Determined order of all the bases
  • Working now to decipher which sequences represent
    which genes and which genes do what
  • Can be useful in synthesizing beneficial
    molecules as medical treatment

  • What does the sentence, We are all the same we
    are all different, mean?
  • Can one genetic group be considered genetically
    superior to another?
  • What has our history taught us?
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  • Why is abortion rates higher among
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Gene transfer
  • Technique of taking a gene out of one organism
    (donor) and placing it in another organism (host)
  • Ex. host tomatoes more resistant to cold and
    frost due to donor DNA from a fish
  • Proteins used by fish to resist icy temp. of
    arctic waters are now produced by the modified
  • Would strict vegetarians be able to eat a tomato
    which has a fish gene in it?
  • What happens to local ecosystems which rely on
    insects that may be killed by Bt crops?

Cutting and pasting DNA
  • scissors made from enzymes
  • Restriction enzymes called endonucleases find and
    recognize a specific sequence of base pairs along
    the DNA molecule
  • Sets of four or six pairs
  • Gene is cut out and released
  • Can then be removed from the donor organism
  • DNA ligase pastes the genes to the sticky ends in
    a particular portion of the DNA sequence

Copying DNA (DNA cloning)
  • Most of the genetic info for E. coli is in the
    single chromosome
  • Some DNA is found in plasmids
  • Plasmids are small circles of extra copies of DNA
    floating around inside the cells cytoplasm
  • To copy a gene, it must be glued into a plasmid

Steps of copying DNA
  • Plasmid is removed from host cell and cut using a
    restriction endonuclease
  • Gene to be copied is placed inside the open
    plasmid using DNA ligase (a.k.a. gene splicing)
  • Recombinant plasmid is used as a vector
  • Vector is placed inside host bacterium
  • Bacterium allowed to grow and proliferate
  • Bacterium expresses the gene and synthesizes
    whatever protein the gene codes for
  • Used to make human insulin

Genetically modified organisms (GMOs)
  • Organisms that has had an artificial genetic
  • Organisms produced to be more competitive in food

Transgenic plants
  • Undesirable gene removed
  • Desirable gene is put in its place
  • New gene is just added
  • Applications
  • Delay ripening
  • Tolerate high salinity
  • Produce beta carotene
  • Could GM plants help solve world hunger?

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Transgenic animals
  • Used to produce a substance which can be used in
    medical treatment
  • Examples
  • Production of factor IX (protein needed for blood
  • Resistance to parasites
  • Pre-dyed wool
  • Show dogs
  • Faster racehorses

Benefits, promises, and hopes for the future
  • GM crops will help farmers by improving food
  • Fewer chemical pesticides will be needed
  • Production of rare proteins for medications could
    be less costly
  • Greater control over crop or livestock production
  • Lower need for water

Harmful effects, dangers, and fears
  • Effect on ecosystems
  • Genes could cross species
  • Toxins to kill insects harmful to humans
  • Allergies
  • Food supply property of small number of
  • May be simpler solutions
  • Decrease in biodiversity

Clones and cloning
  • Clone group of genetically identical organisms
    or a group of cells artificially derived from a
    single parent
  • Fertilized eggs do not differentiate until after
    dividing many times
  • It was once thought that once differentiated, the
    cell could not be used to produce a clone
  • In 1996, a sheep named Dolly was born
  • First clone whose genetic material did not
    originate from an egg cell

How Dolly was produced
  1. Somatic cell from donor sheep udder was collected
    and cultured nucleus removed
  2. Unfertilized egg collected from another sheep
    nucleus removed
  3. Using a zap of electrical current, the egg cell
    and the nucleus from the cultured somatic cell
    were fused together

  • New cell developed in vitro and started to form
    an embryo
  • Embryo placed in the womb of a surrogate mother
  • Embryo developed normally
  • Dolly was born and presented as a clone of the
    original donor sheep
  • Known as reproductive cloning

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Cloning using undifferentiated cells
  • Therapeutic cloning involves the copying of
    cells, not an entire individual
  • Aim is to develop cells which have not yet gone
    through differentiation
  • Involves embryonic stem cells

Ethical issues surrounding therapeutic cloning
  • Is it ethically acceptable to generate a new
    human embryo for the sole purpose of medical
  • Thanks to stem cell research may be able to
  • Grow skin to repair a serious burn
  • Grow new heart muscle
  • Grow new kidney tissue to rebuild a failing kidney