Transcript Biotechnology Technique #3: Genetic Engineering

Biotechnology Technique #3: Genetic
Engineering
• Use the slides that follow to fill in the notes on
page 6 of your note packet.
This is Buckey and Tucker
alongside their mom.
Buckey and Tucker have
been genetically
engineered so that their
female offspring will
produce a specific protein
in their milk.
There are several ways that organisms
can develop new traits:
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natural selection
mutation
selective breeding
genetic engineering
• We’re going to look at the last two in this
chapter.
Selective Breeding
• Selective breeding = artificial selection
(instead of natural selection)
• Process of breeding plants or animals for
specific traits
• animals = breeds
• plants = varieties or cultivars
With selective breeding…
• Humans take control; we choose the traits
that we want the offspring to have:
– Identify the feature that we want
– only allow individuals with that feature to breed
with one another
• We’ve been doing this for 1000s of years!
– crops
– domesticated animals
Examples
• Farmers select for cows that produce more
milk or for corn plants that produce corn with
larger ears
• Dog breeders
Genetic Engineering
• Genetic engineering = altering the DNA of
living organisms
• Requires recombinant DNA
• Recombinant DNA (rDNA) is DNA from two or more
sources incorporated into a single recombinant molecule
• Organisms with rDNA are genetically modified organisms
(GMOs)
• Has both medical and agricultural
applications!
• Use the slides that follow to fill in the
information on page 7 of your note packet.
This is Dolly, the first successfully
cloned organism, and her lamb,
Bonny.
Medical Application 1
• Gene therapy
– Isolate healthy functional gene
– Insert healthy gene into a vector like bacteria or a virus
– Infect a patient with the vector to introduce the healthy
gene
– The healthy gene should produce a normal protein that
replaces the function of the patient’s abnormal protein
• Works well for disorders resulting from loss of single proteins
• Gene therapy is a possible treatment for people suffering
from cystic fibrosis, hemophilia, possibly AIDS and some
cancers
• Cons:
– treatment must be repeated
– immune reactions
Medical Application 2
• Cloning – whole organisms = cloning by Somatic
Cell Nuclear Transfer (SCNT)
• 1st done in 1996 – Dolly
• Died of premature aging and disease
• 6 yrs old – about ½ the normal life span
• Goal is to alter genome in a useful way
– Exp. altered/cloned goats secrete human clotting
factors
– Altered pigs may produce organs for transplant that
don’t trigger rejection
Medical Application 3
• Vaccines
– Some vaccines contain genetically altered
pathogens so they do not cause disease but the
body sill builds up antibodies/immune response
against the pathogen in the future
• Exp. DNA vaccines have pathogen DNA but no
disease-causing capabilities
• Possibilities: AIDS, malaria, cancers
Medical Application 4
• Genetically engineered bacteria can become
like little “protein factories” that produce
human proteins
• Scientists can isolate and purify these proteins
for human use
– Exp. insulin for diabetics
• There are over 30 products made this way for
medical use!
A Few Recombinant DNA products:
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Insulin – for diabetics
Factor VIII and factor IX – clotting factors for hemophiliacs
Human growth hormone – for growth defects
Erythropoietin – for anemia
Interferons – for viral infections and cancer
Interleukins
Tissue plasminogen activator – dissolves blood clots
Angiostatin and endostatin – cancer drugs
Hepatitis B surface antigen – for hepatitis B vaccine
Agricultural applications
• Genetically modified organisms (GMOs)
include crops and livestock.
Agricultural applications
• Genetically modified crops have been
genetically altered to:
– be more tolerant of environmental conditions
– be resistant to insects/pests and herbicides (weed
killers)
• Have genes that code for proteins that are harmful to
insects/pests
– be resistant to plant diseases
– increase the amount of food a crop will yield
– improve nutritional value
GMOs
• 93% of soy
• 94% of cotton
• 88% of corn
• GMOs in > 80% of packaged products!
• Although polls consistently show that American
consumers would like to have foods labeled as
containing GMOs, there are no mandatory
labeling laws.
• Livestock have been genetically altered to
– Increase milk production
– Increase growth rate
– Be more resistant to infections
– Produce leaner meat
• No GM animals have been approved for food
by the FDA yet…
• Remember Buckey and
Tucker? They’ve been
engineered so that their
female offspring will
produce spider silk protein
in their milk.
• Huh?! Why? That sounds
weird.
• These proteins can be used
to spin silk fibers needed to
make artificial limbs and
bulletproof vests!
Why the controversy over genetic
technology?
• GM crops can get into the wild and become a
“SUPERWEED”!
• Gene therapy shouldn’t involve reproductive cells that
could affect future generations.
• Human embryos should not be cloned.
• Confidentiality is key. Knowing an individual’s genetic
make up may lead to discrimination in the workplace.
• As much as 70-75% of food in supermarket may be
genetically modified. The US does not require GM foods
to be labeled.
The End!!
Thank you for completing your notes!!