Gene Technology

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Gene Technology

• Genomics - the study of entire genomes
• Human genome project
• Began in 1990
• International effort to sequence the human
  genome.
• 2.9 billion DNA base pairs in the human genome
• Sequenced and mapped 25,000 genes

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Human Genome Project

• Findings
• Suprisingly few genes for the large human genome
• Most DNA is non-coding does not code for a
  protein
• Many genes found in humans are the same as in
  other species
• All humans are almost genetically identical

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Manipulating genes

• Genetic engineering moving genes from one
  organism into another
• DNA extracted out of cells using a simple
  chemical process. Cells are opened and then DNA
  is separated from the rest of the cell parts.

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Gene manipulation

• Specific sequences of DNA can be excised out of
  the genome of organisms.
• Ex. Gene for human insulin
• Restriction enzymes - enzymes that cleave DNA at
  specific sequences of nucleotides.
• Cuts it down into more manageable pieces

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Restriction enzymes

• Sticky ends - overhang created by some
  restriction enzymes cutting in an offset manner.
  
• Blunt ends - cleavage that leaves DNA cut
  straight across.

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Recombinant DNA

• Cloning vector - a carrier that is used to clone
  a gene and transfer it from one organism to
  another.
• Plasmid ring of DNA found in bacterium in
  addition to its main chromosome.

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Recombinant DNA

• Donor gene - a specific gene isolated from an
  organism
• Ex. Insulin gene needed to produce insulin for
  diabetes patients
• Recombinant DNA - the combination of DNA from two
  or more organisms.
• The donor gene can be placed into an organism to
  give it a new characteristic.
• Organisms with recombinant genes may be called
  transgenic, recombinant, or genetically modified.
  

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Genetically Modified or Transgenic Organisms

• Genetic engineering is used to create GMOs used
  in agriculture, medicine, industry, and basic
  research.
• Bioremediation using microbes for environmental
  cleanup.
• First GMO was a genetically engineered bacterium
  that can digest oil.

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Food Crops

• Bacillus thuringiensis (Bt) gene that produces
  insecticide is inserted to many crops.
• Transgenic rice with added vitamin A reduced
  vision impairment in Asian countries.
• Crops can also be modified to make them easier to
  grow and to increase nutrition values.

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Livestock

• Livestock engineered to grow faster, more muscle,
  less fat, and even more milk with specific
  proteins in it.
• Some GMOs are sold as unique pets

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Medicinal uses

• Gene for insulin is spliced into cloning vector
  and inserted into a bacterium to produce needed
  protein for diabetes patients.
• Hemophilia patients also are treated with
  proteins produced this way.

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MRSA

• Due to the excessive use of antibiotics a new
  bacteria that is resistant to multiple
  antibiotics has grown rampant.
• MRSA is a type of Staphylcoccus aureus that has
  developed resistance to penicillin and
  methicillin, the two drugs normally used to treat
  staph infections.

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Gene therapy

• Gene therapy replacing an absent or faulty gene
  with a working one.

• Copies of normal gene are cloned by bacteria and
  then inserted into viruses or transport vesicles.
  
• Limited success because human body has many
  protections against the invasion and genetic
  change that viruses cause.
• Used to treat cystic fibrosis today. These
  patients have a defective gene for an enzyme in
  secretory cells.

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Stem cells

• Unspecialized cells that have the potential to
  differentiate.
• Bone marrow cells give rise to various blood
  cells.

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Stem Cells

• Cells in new embryos are able to develop into any
  type of cell except germ cells.
• They can be grown in tissue cultures.
• Tissues can be re-implanted into a patient whose
  tissues are damaged.

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Cloning

• Clone member of a population of genetically
  identical cells produced from a single cell.
• Ex. Asexual reproduction in bacteria, budding in
  plants and fungi, and self-fertilization of
  plants and animals
• Very few large animals can clone themselves.
• In 1997, Scottish scientist Ian Wilmut announced
  he had cloned the first mammal, a sheep named
  Dolly.

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Ethical and Social Issues

• What do you think about stem cell
• research, genetically modified
• organisms, and cloning? Should it be allowed? Do
  the benefits out way the risks?

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More DNA Technologies

• Gel electrophoresis electric current used to
  separate fragments of DNA.
• DNA fingerprint pattern of bands created by
  fragments from an individuals DNA.
• Used in Forensics to indicate who was at the
  scene of a crime.

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DNA Fingerprints

• Which of the suspects committed the crime?

1. Suspect 1
2. Suspect 2
3. The boyfriend
4. None of the above

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Polymerase Chain Reaction (PCR)

• PCR process that replicates DNA sequences
• Place host DNA, primers, polymerase, and
  nucleotides in a test tube and control
  temperature to start and repeat process over and
  over again.

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Other DNA Technologies

• Probe short DNA or RNA strand with attached
  radioactive or fluorescent materials to tag
  specific sequences.
• Nucleotide sequences are complementary to the
  gene of interest
• Southern blot used to indicate certain
  fragments that hybridized with a probe.

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DNA Sequencing

• The process of determining the exact order of
  every nucleotide in a gene.