DNA TECHNOLOGY

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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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CONNECTION
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• 12.7 DNA technology is changing the
  pharmaceutical industry
• DNA technology
• Is widely used to produce medicines and to
  diagnose diseases

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What is biotechnology?

• The use of living organisms to do practical
  tasks.
• 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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What is the goal of biotechnology?

• To find practical applications of DNA tecniques
  for the improvement of human health and food
  production
• Examples
• 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 manipulatingplant genes
  and making transgenic plants.

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The tools of recombinant DNA

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

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BACTERIAL PLASMIDS AND GENE CLONING
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• 12.1 Plasmids are used to customize bacteria An
  overview
• Gene cloning is one application of DNA technology
• Methods for studying and manipulating genetic
  material

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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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• 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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Gene therapy may someday help treat a variety of
diseases
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• Gene therapy
• Is the alteration of an afflicted individuals
  genes

Cloned gene (normal allele)
Viral nucleic acid
Retrovirus
Bone marrow cell from patient
Bone marrow
Figure 12.13
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• 12.11 Restriction fragment length polymorphisms
  can be used to detect differences in DNA sequences

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• How Restriction Fragments Reflect DNA Sequence
• Restriction fragment length polymorphisms (RFLPs)
• Reflect differences in the sequences of DNA
  samples

Figure 12.11A
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CONNECTION
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• 12.9 DNA microarrays test for the expression of
  many genes at once
• DNA microarray assays
• Can reveal patterns of gene expression in
  different kinds of cells

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• DNA microarray

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DNA microarray
Each well contains DNA from a particular gene
Actual size (6,400 genes)
Reverse transcriptase and fluorescent
DNA nucleotides
Nonfluorescent spot
Fluorescent spot
cDNA
DNA of an expressed gene
DNA of an unexpressed gene
Figure 12.9
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• 12.10 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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• 12.11 Restriction fragment length polymorphisms
  can be used to detect differences in DNA sequences

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• Using DNA Probes to Detect Harmful Alleles
• Radioactive probes
• Can reveal DNA bands of interest on a gel

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• Detecting a harmful allele using restriction
  fragment analysis

Figure 12.11C
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CONNECTION
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• DNA technology is used in courts of law

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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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• DNA fingerprinting can help solve crimes

Figure 12.12A
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Safety and ethical issues
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• Methods for purifying the DNA
• Vectors for carrying the DNA into cells and
  replicating it
• Techniques for determining nucleotide sequences
  of DNA molecules