In this lesson we

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In this lesson we

• examine the use of DNA technology in forensics,
  medicine, and agriculture (SB2f)
• Terms and topics related to DNA Technology
• Biotechnology
• cloning
• DNA fingerprinting
• genetic engineering
• Human Genome Project
• plasmid
• recombinant DNA

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What is biotechnology?

• The use of living organisms to do practical
  tasks.
• Early examples
• The use of microorganisms to make cheese and wine
• Selective breeding of livestock and crops
• Production of antibiotics from microorganisms
• Production of monoclonal antibodies

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Goal of biotechnology today

• To find practical applications of DNA tecniques
  for the improvement of human health and food
  production
• Making gene products using Genetic Engineering
• Uses in basic research
• Medical uses. Diagnosis of disease
• Making vaccines and other pharmaceutical products
  
• Forensic uses of DNA such as DNA fingerprinting
• Agricultural uses such as making transgenic
  plants

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DNA Technology

• What we can do with DNA and what it can do for us

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DNA TECHNOLOGY

• DNA recombination or genetic engineering is the
  direct manipulation of genes for practical
  purposes

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Recombinant DNA technology

• Refers to the set of techniques for combining
  genes from different sources in vitro( in a test
  tube) and transfering this DNA into a cell so it
  can be expressed.
• These techniques were first developed around 1975
  and resulted in the appearance of the
  Biotechnology industry

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The tools of recombinant DNA

• Plasmids
• Restriction enzymes
• Gel electrophoresis
• PCR ( polymerase chain reaction)

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• Researchers can insert desired genes into
  plasmids, creating recombinant DNA
• And insert those plasmids into bacteria

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Bacterium
Cell containing gene of interest
Plasmid
Bacterial chromosome
DNA
Recombinant DNA (plasmid)
Gene of interest
Recombinant bacterium
Copies of gene
Copies of protein
Clone of cells
Gene for pest resistance inserted into plants
Protein used tomake snow format
highertemperature
Figure 12.1
Gene used to alter bacteria for cleaning up toxic
waste
Protein used to dissolve bloodclots in heart
attack therapy
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Genetic Engineering

• DNA from one species is inserted into another
  species.
• Ex. Human Insulin for diabetics is now made by
  bacteria cells!

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• Therapeutic hormones
• In 1982, humulin, human insulin produced by
  bacteria
• Became the first recombinant drug approved by the
  Food and Drug Administration

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Restriction enzymes cut DNA at specific sequences
in the DNA
Restriction enzymes scissors
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Recombinant DNATwo pieces of DNA cut with the
same restriction enzyme will be able to
re-combine with each other.
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Plants

• 1) Examples of transgenic plants with resistance
  to viruses
• potatoes, tomatoes, tobacco
• 2) Examples of transgenic plants with resistance
  to insects corn, cotton
• 3) resistance to herbicides
• 4) slow down spoilage in tomatoes
• 5) Extreme example strawberries that are
• resistant to drought, salt, insects, viruses,
  
• cold and frost, and improved taste

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Animals

• Bacteria now produce all of the following
• Human growth hormone (HGH)
• Human insulin (replaced cow and pig insulin for
  human therapy )
• Follicle-stimulating hormone
• Factor VIII (replaced clotting factors taken from
  human blood.)

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Electrophoresis

• Separation of charged molecules in an electric
  field.
• Nucleic acids have 1 charged phosphate (- charge)
  per nucleotide. Separation based (mostly) on
  length longer molecules move slower.
• Done in agarose gel matrix to stabilize.
• average run 100 Volts across a 10 cm gel, run
  for 2 hours.
• Stain with ethidium bromide bonds between DNA
  bases and fluoresces orange.
• Run alongside standards of known sizes to get
  lengths

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• Gel electrophoresis sorts DNA molecules by size

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• After digestion by restriction enzymes
• The fragments are run through a gel

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Crime

• Forensic science is the use of scientific
  knowledge in legal situations.
• The DNA profile of each individual is highly
  specific.
• The chances of two people having exactly the same
  DNA profile is 30,000 million to 1 (except for
  identical twins).

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• DNA and Crime Scene Investigations
• Many violent crimes go unsolved
• For lack of enough evidence
• If biological fluids are left at a crime scene
• DNA can be isolated from them

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• DNA fingerprinting is a set of laboratory
  procedures
• That determines with near certainty whether two
  samples of DNA are from the same individual
• That has provided a powerful tool for crime scene
  investigators

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DNA Fingerprinting

• 1st-The DNA molecule is cut with restriction
  enzymes
• 2nd- we have to separate the fragments
• This is done by a technique called gel
  electrophoresis
• The DNA is placed on a tray filled with gel
  through which an electric current runs causing
  the fragments to move through the gel. The
  segments separate by how far they move in the gel
  according to size.
• The DNA will form bands corresponding to the
  bases (and no two people have the same sequence
  of bases) in the gel which are unique for each
  individual. This is DNA fingerprinting

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Example

• A violent murder occurred.
• The forensics team retrieved a blood sample from
  the crime scene.
• They prepared DNA profiles of the blood sample,
  the victim and a suspect as follows

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Does suspect DNA bands match DNA from the crime
scene?
Suspects Profile
Blood sample from crime scene
Victims profile
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• DNA fingerprinting can help solve crimes

Figure 12.12A
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DNA Fingerprinting

• Gel Electrophoresis
• separates pieces of DNA based on size
• (after being cut up with restriction enzymes)
• Different people will have different banding
  patterns.
• Related individuals will have similar patterns.

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Solving Medical Problems

• DNA profiles can be used to determine whether a
  particular person is the parent of a child.
• A childs paternity (father) and maternity(mother)
  can be determined.
• This information can be used in
• Paternity suits
• Inheritance cases
• Immigration cases

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Example A Paternity Test

• By comparing the DNA profile of a
• mother and her child it is possible to
• identify DNA fragments in the child
• which are absent from the mother and
• must therefore have been inherited
• from the biological father.

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Does this mans DNA match the DNA of the child?
Mother
Child
Man
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Cloning organisms

• A body cell from one organism and an egg cell
  from another are fused
• The resulting cell divides like a normal embryo

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Cloning

• Clone- a member of a group of genetically
  identical cells
• May be produced by asexual reproduction (mitosis)

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What is cloning?

• Reproductive cloning
• Making an exact copy of a pre-existing or
  currently existing organism.
• Therapeutic cloning
• Embryos are grown and stem cells from the embryo
  are harvested to be used in research to develop
  treatment for cancer, Alzheimers, etc.
• Very controversial b/c it kills the embryo in the
  process.

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Human Genome Project

• Started 1988, finished 2001, the entire sequence
  of bases in human DNA is now known.
• This multi-national effort has led to increased
  knowledge of
• Human genetic diseases
• Gene therapies
• Evolutionary relationships
• Cellular functions
• Cancer genes

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Gene Libraries

• Human genes (and other genes of interest) can be
  stored inside bacteria cells and viruses which
  can be saved and grown for use in research.
• This may also preserve the genes of endangered
  or extinct species.

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Review and Summarize

• -use of DNA technology in forensics, medicine,
  and agriculture (SB2f)
• Terms and topics related to DNA Technology
• biotechnology
• Cloning
• DNA fingerprinting
• genetic engineering
• Human Genome Project
• plasmid
• recombinant DNA