Transcript Genetic Engineering - Ms Kim's Biology Class

Bellringer-December 3, 2013
• Is genetic engineering a new technology
(last 25 years)? Around when do think
genetic engineering started?
• Have you eaten GMOs?
• What crops do you think have the highest
likelihood of being GMOs?
Genetic Modification
Two Methods
• Selective Breeding (breeding plants or animals based
on selecting desirable characteristics of the parent)
• Recombinant DNA (genetic engineering)  GMO
• Genetic Engineers can change the DNA code (genes) of
living organisms.
Natural Selection vs.
Artificial Selection
• In artificial selection (selective
breeding),
• humans modify other species over
many generations by selecting and
breeding individuals with desired
traits
Selective Breeding
• Breed only those
plants or animals with
desirable traits
• People have been
using selective
breeding for
thousands of years
with farm crops and
domesticated
animals.
Selective Breeding
•
The evolution of corn or maize
(Zea mays) involved the gradual
increase in the size of the grain
head (ear) shown here, as well as
the development of varieties that
would tolerate the prevailing
climatic conditions in different
areas of the New World.
How does it work?
In cross pollination (think Mendel’s 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
Genetic EngineeringRecombinant DNA
• The ability to combine the
DNA of one organism with
the DNA of another
organism. This is where
genes from one species can
be introduced into an
entirely different species
through human intervention.
• An organism that is
generated through genetic
engineering is considered to
be a genetically modified
organism (GMO).
• Recombinant DNA
technology was first used in
the 1970’s with bacteria.
History?
• The first GMOs were bacteria in 1973; GM mice
were generated in 1974. Insulin-producing
bacteria were commercialized in 1982 and
genetically modified food has been sold since
1994. Glofish, the first GMO designed as a pet,
was first sold in the United States December in
2003.
Recombinant Bacteria
1.
Remove bacterial DNA
(plasmid).
2.
Cut the Bacterial DNA with
“restriction enzymes”.
3.
Cut the DNA from another
organism with the SAME
“restriction enzymes”.
4.
Combine the cut pieces of DNA
together with another enzyme
and insert them into bacteria.
5.
Reproduce the recombinant
bacteria.
6.
The foreign genes will be
expressed in the bacteria.
How to Create a Genetically
Modified Plant
1.Create recombinant
bacteria with desired
gene.
2. Allow the bacteria to
“infect" the plant cells.
3. Desired gene is
inserted into plant
chromosomes.
Bacterium
Cell containing gene
of interest
Plasmid
Bacterial
chromosome
Gene of
interest
DNA of
chromosome
Recombinant
DNA (plasmid)
• Overview of
gene cloning
with a bacterial
plasmid,
showing
various uses of
cloned genes
Figure 20.2
Recombinant
bacterium
3
Gene of
interest
Protein expressed
by gene of interest
Copies of gene
Protein harvested
Basic
research
on protein
Basic
research
on gene
Gene for pest
resistance inserted
into plants
Gene used to alter
bacteria for cleaning
up toxic waste
Protein dissolves
blood clots in heart
attack therapy
Human growth
hormone treats
stunted growth
Transgenic
• If genetic material from another species is
added to the host, the resulting organism is
called transgenic.
• Trangenic organisms are a subset of
GMOS. They are a subset of GMOs
because they are the species in which their
DNA is inserted into another species.
Examples
• For example, taking a gene from a
jellyfish and inserting into the
zebrafish genome created the
“glofish” – fish that glow in the dark
which are now being sold on the
market.
• Another example is genes from a
bacteria inserted into food crops so
that the crop can create it’s own
insecticide. These plants and animals
are also known as “transgenic”.
How to Create a
Transgenic Animal
Desired DNA
is
added to an
egg cell.
The DNA of plants and animals
is altered for several reasons
PLANTS
1.
2.
3.
4.
Disease-resistant
Insect-resistant crops
Hardier and bigger fruit
Increased vitamin
content
5. “Pharming” purposes
(ex. Vaccine)
70-75% of food in
supermarket is
genetically modified.
What are
Genetically
Modified Foods?
(“Frankenfoods”?)
You have already eaten GM foods. Some GM
tomatoes, for example, have had their genes
altered to stop them from going soft while they
are still growing. For several years they were
widely sold in tomato paste.
The GM foods we eat have all been tested for
safety. But some people worry about the long
term effects of eating genetically modified
foods!
What Have I Eaten?
Genetically modified
(GM) foods possess
specific traits such
as tolerance to
herbicides or
resistance to insects
or viruses.
Likely GMO Crops
Alfalfa (first planting 2011)
Canola (approx. 90% of U.S. crop)
Corn (approx. 88% of U.S. crop in 2011)
Cotton (approx. 90% of U.S. crop in 2011)
Papaya (most of Hawaiian crop; approximately
988 acres)
Soy (approx. 94% of U.S. crop in 2011)
Sugar Beets (approx. 95% of U.S. crop in 2010)
Zucchini and Yellow Summer Squash (approx.
25,000 acres)
ALSO high-risk: animal products (milk, meat, eggs,
honey, etc.) because of contamination in feed.
http://www.nongmoproject.org/l
earn-more/what-is-gmo/
Can We End World Hunger? Malnutrition
and vitamin deficiencies?
Golden rice is genetically modified rice that now
contains a large amount of A-vitamins. Or more
correctly, the rice contains the element beta-carotene
which is converted in the body into Vitamin-A. So when
you eat golden rice, you get more vitamin A.
Advantages:
•The rice can be considered a particular advantage to poor people in
underdeveloped countries. They eat only an extremely limited diet lacking in
the essential bodily vitamins. The consequences of this restricted diet causes
many people to die or become blind. This is particularly true in areas of Asia,
where most of the population live on rice from morning to evening.
Going Bananas?
According to recent reports, the world may
soon be out of bananas.
Bananas are propagated through asexual
cloning, so all bananas are genetically
identical
Banana plantations in Africa, Asia and
Central America are uniquely susceptible to
fungi, viruses and pests.
http://gslc.genet
ics.utah.edu/fea
tures/gmfoods/
Unless scientists can find a way to
genetically enhance the banana’s ability to
ward off parasites, we could be bananaless
in ten years.
Genetically modified organisms are
called transgenic organisms.
TRANSGENIC ANIMALS
1.
Fish – grow faster than
normal aquaculture salmon
2.
Chickens – more resistant to
infections
3.
Cows – increase milk supply
and leaner meat
4. Goats, sheep and pigs –
produce human proteins in
their milk
Transgenic Goat
Human DNA in
a Goat Cell
This goat contains a human
gene that codes for a blood
clotting agent. The blood
clotting agent can be harvested
in the goat’s .milk.
Transgenic Fish
• AquAdvantage salmon grow
twice as fast as wild Atlantic
salmon.
http://www.nature.com/news/transgenicfish-wins-us-regulatory-backing-1.12130
Researchers are also
working to bring GM cows,
chickens and pigs to
market.
• Food and Drug
Administration (FDA) is in
the final stages of deciding
whether to allow GM
salmon on to the market.
• Aldi and Whole Foods
among retailers refusing to
sell product
Are they Safe?
•
The GM products that are
currently on the international
market have all passed risk
assessments conducted by
national authorities.
•
These different assessments
include an assessment of
environmental and human health
risk.
•
These assessments are thorough,
they have not indicated any risk to
human health.
http://www.who.int/foodsafety/public
ations/biotech/20questions/en/
Is it
safe to eat? Why isn't it labeled
in the U.S.?
• The U.S. government's position: Genetically engineered crops are safe,
resist disease better, and can provide much-needed food in starving
nations.
• The EU position: Keep it out. We prefer organic, which is much healthier.
The risk of genetically modified foods to health and the environment
outweigh the benefits. Only the multinational biotech companies will
benefit, dominating the world food supply and squeezing out traditional
farmers.
• The U.S. is the largest producer of genetically modified crops.
'Frankenfood' Fears
Experts say this science, like any other, has no
guarantees. Risks include:
• Introducing allergens and toxins to food
• Accidental contamination between genetically modified and
non-genetically modified foods
• Antibiotic resistance
• Adversely changing the nutrient content of a crop
• Creation of "super" weeds and other environmental risks
Benefits include:
• Increased pest and disease resistance
• Drought tolerance
• Increased food supply
Monsanto
•
•
•
Monsanto Company is a publicly traded American multinational chemical,
and agricultural biotechnology corporation headquartered in Creve Coeur,
Missouri.
It is a leading producer of genetically engineered (GE) seed and of
the herbicide glyphosate, which it markets under the Roundup brand.
Monsanto was among the first to genetically modify a plant cell, along with
three academic teams, which was announced in 1983, and was among the
first to conduct field trials of genetically modified crops, which it did in 1987
Consumer
Attitudes
•
Many consumers more readily accept biotechnology as beneficial for their health (e.g.
medicines with improved treatment potential).
•
In the case of the first GM foods introduced onto the European market, consumers felt
the products were of no apparent direct benefit to (not cheaper, no increased shelf-life,
no better taste).
•
Consumers have questioned the validity of risk assessments, both with regard to
consumer health and environmental risks, focusing in particular on long-term effects.
•
Other topics for debate by consumer organizations have included allergenicity and
antimicrobial resistance.
•
Consumer concerns have triggered a discussion on the desirability of labelling GM foods,
allowing an informed choice. At the same time, it has proved difficult to detect traces of
GMOs in foods: this means that very low concentrations often cannot be detected.
Pros and Cons
Crops
• Better taste and quality
• Less time to ripen.
• More nutrients, more food, and stress
tolerance
• Improved resistance to disease, pests, and
herbicides
• New products and growing techniques
Animals
• Increased resistance, productivity, hardiness,
and feed efficiency
• Better yields of meat, eggs, and milk
• Improved animal health and diagnostic
methods
Environment
• "Friendly" bioherbicides and bioinsecticides
• Conservation of soil, water, and energy
• Better natural waste management
• More efficient processing
Society
• More food for growing populations
Safety
• Potential human health impact: allergens,
transfer of antibiotic resistance markers,
unknown effects
• Potential environmental impact: unintended
transfer of transgenes through cross-pollination,
loss of flora and fauna biodiversity
Access and Intellectual Property
• Domination of world food production by a few
companies
• Increasing dependence on Industralized
nations by developing countries
Ethics
• Violation of natural organisms' intrinsic values
• Tampering with nature by mixing genes among
species
• Objections to consuming animal genes in plants
and vice versa
• Stress for animal
Labeling
• Not mandatory in some countries (e.g., U.
States)
• Mixing GM crops with non-GM confounds
labeling attempts
Bizarre examples
Glow in the dark
cats
Venomous
Cabbage
(scorpion
poison)
Exit Slip
1. What the two methods of genetic
modification?
2. What are two reasons GMOs are
engineered?
3. Name and explain one example of the
positive effects of GMOs.
4. Name at least two likely GMO crops.
5. What two areas of risk do the risk
assessment assess?