GENETIC ENGINEERING

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GENETIC ENGINEERING

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That's Unbelievable!
Genetic engineering examples include taking the
gene that programs poison in the tail of a
scorpion, and combining it with a cabbage.  These
genetically modified cabbages kill caterpillers
because they produce scorpion poison
(insecticide) in their sap. Potatoes have been
engineered to resist pests by producing a
chemical coded for by a frog gene. Genetic
engineering also includes insertion of human
genes into sheep so that they secrete alpha-1
antitrypsin in their milk - a useful substance in
treating some cases of lung disease.
Genetic engineering works because there is one
language of life (universal genetic code) 
human genes work in bacteria, monkey genes work
in mice, pepper plant genes work in bananas and
spider genes work in goats.  There is no limit,
in theory, to what genetic engineering could
produce!
Genetic engineering has created a chicken with
four legs and no wings. Scientists were studying
the genes that control limb formation in embryo
development.
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What is genetic engineering?

• the use of technology to change the genetic
  make-up of cells to produce a new and useful
  result

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Is genetic engineering a new idea?

• Humans have been selecting and breeding organisms
  with desired traits for thousands of years. Some
  examples
• Seedless oranges
• Pluots Plum-apricot hybrid

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Comparing selective breeding and genetic
engineering
In selective breeding (think Mendels peas), we
are combining two traits to get a mixture of
results
In genetic engineering, a single gene, a half
page recipe in the 52-thousand-page set of recipe
books, can direct the plant to make new traits or
remove them
Comparison
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How does genetic engineering work?

• First, a desired gene in an organism must be
  identified and isolated.
• Once isolated, the gene is further modified in
  the lab
• The modified gene is inserted into a vector (like
  a bacterium or virus) and the vector delivers
  the gene to the desired organism.

http//cmbi.bjmu.edu.cn/cmbidata/therapy/research/
re02/021.htm
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How it works
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Example Insulin Production

• Protein that codes for insulin production is cut
  from human DNA using restriction enzyme (EcoRI)

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Example Insulin Production

• Plasmid (from E.coli) is also cut with EcoRI
• Sticky ends are now exposed on both human DNA and
  plasmid DNA

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Example Insulin Production

• Ligase seals sticky ends of desired DNA and
  plasmid DNA
• Recombinant DNA is inserted into a bacterium

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How Did They Do That?

1. Jellyfish make a protein that causes them to glow
   in some types of light.
2. The glowing gene is taken from a jellyfish cell
   and inserted into an empty virus cell
3. The genetically engineered virus attaches itself
   to the fertilized mouse egg cell.
4. The virus delivers the glowing gene into the egg
   cell nucleus, where it joins the mouse DNA.
5. The genetically engineered mouse egg grows into
   an adult mouse which will make the glowing
   protein.

Jellyfish cell
Virus
Virus inserting their DNA into a cell
Mouse cell
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Transgenic Organisms

• Any organism that contains genes from a different
  organism (traits not normally found in that
  species) is a transgenic organism.

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What are some possible uses of genetic
engineering?

• Improving crops
• Creating bacteria that can produce medicine
• Increasing food supplies
• Alternative energy sources
• Human body parts for transplant
• Preventing human diseases (gene therapy)

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Improving Crops

• Crops may be improved by making them resistant to
  certain factors, like insects, drought,
  herbicides, or frost
• Crops may also be improved by engineering them
  to produce things like vitamins that are not
  normally found in the species

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Agriculture Transgenics On the Market

• Insect resistant cotton Bt toxin kills the
• cotton boll worm
• transgene Bt protein

Source USDA

• Insect resistant corn Bt toxin kills the
• European corn borer
• transgene Bt protein

Bt Corn
Normal
Transgenic
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• Herbicide resistant crops
• Now soybean, corn, canola
• Coming sugarbeet, lettuce, strawberry
• alfalfa, potato, wheat (2005?)
• transgene modified EPSP synthase or
• phosphinothricin-N-acetyltransferase

Source Monsanto

• Virus resistance - papya resistant to
• papaya ringspot virus
• transgene virus coat protein

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Fishy Strawberries- Making a frost resistant
strawberry
1. Fish antifreeze gene is inserted into a
plasmid.
The flounder is a fish that live in icy seas. It
has a gene that stops it from freezing to
death. Strawberries are soft fruits that can
easily be damaged by frost.
2. Plasmid with gene is placed into a bacterium.
3. The bacterium with the flounder gene is used
to infect strawberry cells.
Strawberry cell with Antifreeze gene
4. The infected cells grow into a frost-resistant
strawberry plant.
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Can genetic engineering end malnutrition and
vitamin deficiencies?

• Golden rice is genetically modified to contain
  large amounts of beta-carotene, which is
  converted by the body into vitamin A
• Vitamin A is important to factor for good vision
  (particularly night vision) and a strong immune
  system.
• Many individuals in poor and underdeveloped
  countries receive inadequate amounts of vitamin A
  in their diets, leading to higher incidences of
  blindness.

Golden rice
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Creating bacteria that can produce medicine

• As you saw in a previous example, bacteria have
  already been engineered to produce insulin
  proteins that can be injected by human diabetics
  to control their diabetes.
• Some other examples
• Bacteria produce human growth hormone to treat
  types of dwarfism
• Producing interferon for cancer treatments

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Increasing Food Supplies

• In many parts of the world, hunger is rampant due
  to limited food resources.
• One possibility is to produce fish species that
  mature more quickly so that they can breed and
  create new generations sooner.

Salmon
http//fish.dnr.cornell.edu/nyfish/Salmonidae/salm
onidae.html
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Alternative Energy Sources

• Fossil fuels are dwindling
• Ethanol (the current alternative) comes mostly
  from corn, which is used as a major food crop in
  most countries
• It would be most beneficial to use waste and
  leftovers for fuel.

Ethanol
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Creating Human Body Parts for Transplant

• Individuals in need of an organ transplant can
  often wait years for a donor organ.
• Organs from other species is not usually an
  option because the immune system attacks such
  transplants as foreign.
• Scientists are researching the possibility of
  inserting human genes into other species so that
  they can grow human organs for transplant.

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Whats Going On Here?
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Some Other Possibilities

• Earlier this decade, scientists at the University
  of Minnesota created pigs that pumped human blood
  (specifically human hemoglobin)

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Preventing and Curing Human Diseases

• Several human diseases (like cystic fibrosis or
  breast cancer) have a genetic component.
• Individuals with these disorders have a mutation,
  or mistake, somewhere in their DNA sequence
• Replacing these mutated sequences with normal
  sequences should fix the problem
• This process is known as gene therapy.

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What is Gene Therapy?

1. Individuals with cystic fibrosis have a faulty
   gene.
2. To fix the problem, a copy of the same gene from
   a healthy person is spliced into a virus.
3. The patients lungs are infected with the virus.
   It delivers the working gene into the patients
   cells. The cells can then make the right protein,
   and the patient can breathe normally.

Alzheimers Disease
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Will We Be Able To Cure Cancer With Gene Therapy?
Cancer happens when body cells grow out of
control. Scientists have found a gene called p-53
which normally keeps cells under control. Some
individuals with cancer may have a non-working
copy of p-53. Experts are now looking for a way
to cure cancer by modifying faulty DNA to make
the p-53 gene work.
Breast Cancer
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What Else?
Using the jellyfish protein to make a naturally
glowing Christmas tree!
Genetically engineered moths that pass on deadly
disease genes to their relatives so they die and
wont be able to destroy crops!
A gene from a spider has been inserted into some
goats. Their milk now contains tiny strands of
spider silk which can be made into a strong,
stretchy rope.
Adding a gene from insect killing bacteria to
cotton so that insects who eat cotton will be
poisoned!
This is only the beginning . . . !