Transcript SBI 4U Genetics 8

Genetics 8:
Production and Regulation of
Genetically Engineered
Organisms
Breakthroughs in Science
 Recombinant DNA has led to so many
possibilities but also many controversies.
 Gene Therapy: the correct form of a
defective gene is inserted into a patient’s
genome.
 Making new animals (ie the zebra fish have
recombinant DNA that causes a fluorescent
colour. Long term safety issues are
unknown)
 Designer children?
 How far should we go?
 Who makes these decisions?
Genetic Engineering
 The alteration of the genetic material of
an organism
 Precise and specific
 We can introduce a mutation to a gene
 We can introduce foreign DNA into a
genome from another organism’s genome
that results in a transgenic organism
 Transgenic bacteria, plants and animals
are commonly refereed to as genetically
modified organisms (GMOs)
Transgenic Bacteria in
Pharmaceuticals
 By putting a gene into a bacterial cell and
making the bacteria create that particular
enzyme or protein for us, we then purify
it and use it for medicine. (Insulin)
 Other examples:
 Human growth hormone
 Tissue plasminogen activator (treats blood
clots)
 Erythropoietin (stimulates red blood cell
production)
 Hepatitis B vaccine
Transgenic Bacteria and
Bioremediation
 Bioremediation is when we use
microorganisms to clean up the
environment because they can convert
toxic chemicals into non-toxic products.
 Bacteria that can naturally break down
crude oils was genetically modified so it
can do so more effectively.
 Others include:
 bacteria that can break down pesticides in
water systems
 Remove sulfur from coal to make cleaner
emissions when coal is burned.
Transgenic Plants
 Started thousands of years ago by
meticulously cross-breeding and artificial
selection.
 Examples of transgenic crops: soybeans,
corn, canola, tomatoes, potatoes.
 Most modifications have to do with
increased tolerance to herbicides, greater
resistance to disease which lead to
increased crop yield, reduced harvesting
costs, reduced pesticide use and slower
spoilage.
 Two ways to make transgenic plants:
biolistic and Ti plasmid methods.
Making Transgenic
Plants: Biolistic Method
 Striking plant cells with tiny
particles of gold or platinum that are
coated with DNA
 Sometimes called the gene-gun
method because they are shot at
high speeds to allow the DNA to
penetrate the cell wall.
Making Transgenic
Plants: Ti plasmid Method
 Ti plasmid stands for tumour-inducing
plasmid that is a naturally occurring
plasmid in the bacterium Agrobacterium
tumefaciens that causes growths on
plants. Part of the Ti plasmid, called the
T-DNA integrates into the plant genome
and causes uncontrolled cell growth.
 Researches have altered the T-DNA of
the Ti plasmid so that it no longer causes
the tumour formation, but still allows for
the gene to integrate into the DNA of the
plant cell.
Controversies…
 Are GMOs safe for human consumption?
 7-10 years of health and safety research first
 Will GMOs affect the environment?
 Vertical gene transfer: transfer of a gene into
the genome of a wild organism.
 Harm that a GMO with insecticidal
protection may have. (ie Bt corn reduces the
affect that bacteria might have on corn, but it
may hurt the monarch butterfly populations)
 Insects may become resistant to these
changes over time anyway.
Transgenic Animals
 A foreign gene is inserted into the
genome of an animal oocyte and is then
fertilized.
 Used to produce fish, pigs, cows, rabbits
and sheep.
 Example: pigs engineered so they can
break down phosphates in their food
better leading to better absorption, less
excreted which then reduces the
phosphate contamination of water
sources.
Gene Pharming
 Transgenic animals that produce
human therapeutic proteins.
 Hormones from sheep
 Plasminogen activator Factor IX that
helps with blood clotting
 Alpha anti-trypsin for emphysema
Mammalian Cloning
 Dolly the sheep was the first
 Since then we have cloned cows,
pigs, mice, dogs and cats.
Questions:
 Page 311 #5 - 9, 12