Ch 15 Genetic Engineering

1 Review Give two practical applications for both
transgenic plants and animals
Make Judgments List reasons why you would or
would not be concerned about eating genetically
modified foods
2 Review Name three uses for recombinant DNA
Apply Concepts Medicines interact with the body’s
proteins. How might normal variations in your genes
affect your response to different medicines
3 Infer Why is DNA fingerprinting more accurate if the
samples are cut with more than one restriction
15.3 Applications of Genetic Engineering
Have you eaten any genetically modified food
Agriculture and Industry
Could lead to better, less expensive, and more
nutritious food as well as less harmful
manufacturing processes.
GM (genetically modified) Crops
One genetic modification uses bacterial genes that
produce a protein known as Bt toxin
Toxin is harmless to humans and most other
animals, but kills insects
Plants with the Bt gene do not have to be sprayed
with pesticides.
Other useful genetic modifications include
resistance to herbicides, which are chemicals that
destroy weeds, and resistance to viral infections.
GM Animals
The U.S. government approved the sale of meat
and milk from cloned animals in 2008
30 percent of the milk in U.S. markets comes from
cows that have been injected with hormones made
by recombinant-DNA
Pigs can be genetically modified to produce more
lean meat or high levels of healthy omega-3 acids.
Combined spider genes into the cells of lactating
Goats began to produce silk along with their milk
Silk is extracted from milk and woven into thread
Also trying to put antibacterial protein in goats for
kids who get sick.
Preventing Disease
Provitamin A deficiencies produce serious medical
problems, including infant blindness
Golden rice is a GM plant that contains increased
amounts of provitamin A
Transgenic sheep and pigs that produce human
proteins in their milk.
Medical Research
Transgenic animals can simulate human diseases in
which defective genes play a role.
Treating Disease
Recombinant-DNA technology can be used to
make important proteins that could prolong and
even save human lives
Insulin, blood clotting factors, human growth
Treating Disease
Gene Therapy
 Process
of changing a gene to treat a medical disease
or disorder
 Absent or faulty gene is replaced by a normal, working
Researchers engineer a virus that cannot reproduce
or cause harm
DNA containing the therapeutic gene is inserted
into the modified virus.
Patient’s cells are then infected with the genetically
engineered virus
Virus will insert the healthy gene into the target cell
and correct the defect.
Genetic Testing
Genetic testing can be used to determine if two
prospective parents are carrying the alleles for a
genetic disorder
Use probes looking for disease-causing alleles
Genetic tests are now available for diagnosing
hundreds of disorders.
Examining Active Genes
DNA microarray
 Technology
to study 100s or 1000s of genes at once to
understand their activity levels.
To compare the genes in cancer cells with genes in
normal cells, the mRNA would first be isolated from
both types of cells
Enzymes are used to copy the mRNA base
sequence into single-stranded DNA labeled with
fluorescent colors -red for the cancer cell and green
for the normal cell.
Mix both samples of labeled DNA
They compete to bind to complementary DNA
sequences already placed in the microarray.
Where the cancer cell
produces more mRNA for a
gene the spot will be red
Where the normal cell
produces more mRNA for
gene the spot will be green
If cell produce equal
amounts of gene the spot
will be yellow.
DNA Fingerprinting
Identify individuals by
analyzing sections of DNA that
may have little or no function
but that vary widely from one
individual to another.
Personal Identification
Restriction enzymes cut a small sample of human
DNA into fragments containing genes and repeats
Gel electrophoresis separates the restriction
fragments by size.
DNA probe detects the fragments that have highly
variable regions, revealing a series of variously
sized DNA bands
If enough combinations of enzymes and probes are
used the pattern of bands can be distinguished
statistically from any other individual in the world.
Genetic fingerprints can be used to help solve
crimes (both human and non human) as well as
The modified traits shown in the graph include
herbicide tolerance (HT) and insect resistance (Bt)
Graph is on pg 363.
Analyze Data Which two crops were most widely
and rapidly adopted
Draw Conclusions Why do you think the levels of
adoption fell at certain points of the period
Predict What do you think will happen to HT
soybeans and HT corn over the nest few yearswhy? Use the graph to support your prediction
Infer Why do you think an increasing number of
farmers have chosen to grow crops with
herbicide tolerance

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