Transcript Genetically Modified Foods What is a Genetically Modified (GM) Food?

Genetically
Modified Foods
What is a Genetically
Modified (GM) Food?
Foods that contain an added gene
sequence
 Foods that have a deleted gene
sequence
 Animal products from animals fed GM
feed
 Products produced by GM organisms

Why are foods
genetically modified?

Genetic engineering offers a rapid
and precise method of altering
organisms as compared to
traditional methods that are slow
and inaccurate.
Examples of GM food
Vegetables
 Tomatoes
 Potatoes
 Rice
 Cheese
 Meat

Their genes are usually modified to make the
crops pest or herbicide resistant
Examples of GM food

1994: Flavr Savr© tomato
– the first approved GM food
product
- tomato genes are usually
modified to delay
ripening and softening
5
How is genetic
modification possible?


The components of DNA are the same in
all organisms.
Sequences that code for proteins can be
moved from one organism to another.
How can DNA be moved from
one organism to another?
Its quite
simple,
REALLY!!!
How can DNA be moved from
one organism to another?
►Find an organism with the desired
trait
►Isolate the gene sequence that
codes for the desired trait
►Insert the gene sequence into the
genome of the plant cell
How can DNA be moved from
one organism to another?
►Allow the genetically altered
cell to grow into a plant
►Allow the plant to propagate
How can DNA be moved from
one organism to another?

A vector can
carry DNA. The
vector can be a
pellet from a
gene gun.
Viruses and
bacteria also can
be utilized to
transfer genes.
Role of GM Foods in EMs

Very important for developing countries/EMs
–
–
–
–

By 2050pop. 9b  food strategy for next 20 yrs
Need more food, as such hunger and starvation
3m deaths/year in Africa solely relating to hunger
3 options: aid/food, money/funds, provide GM foods
GM foods: Rapid, accurate,↑ yield, ↓labor, ↑shelf-life
Advantages of GM Foods…

Pest resistance
– Crop loss due to insets  financial loss to farmers
– So, farmers use tons of pesticides/fertilizers annually
– GM eliminates pesticides and thus ↓ cost of production

Disease resistance
– Viruses, fungi, bacteria  plant diseases
– GM crops resistance to these diseases

Cold resistance

Frost can destroy sensitive seedlings
– Antifreeze gene from cold fish  tobacco and potatoes
Advantages of GM Foods

Drought resistance
– More population  ↑ land for housing, ↓ land for farming
– Land unsuited for plant cultivation  Africa, dessert
– GM crops  grow in draughts or ↑ salt-content soil

Nutrition
–
–
–
–

Single crop (rice) cannot give all the nutrition needed
Lack vitamin A  blindness  common in EMs
GM food: golden rice has Vitamin A (beta-carotene)
GM food: with enhanced iron is underway, Europe?
Pharmaceuticals
– Edible vaccines in tomatoes and potatoes
– Easier to ship, store, administer than traditional injections
Criticism of GM
Organism/Foods…
Criticism of GM Foods…

Environmental hazards
– Unintended harm to other organism

Difficult to design toxin  kills crop-damaging pests, not other
insects
– Reduced effectiveness of pesticides

Develops resistance  DDT
– Gene transfer to non-target species




Cross-breeding
Transfer of herbicide resistance from crops to weeds
The “superweeds” will then have herbicide tolerance as well
Solution
– Create buffer zone
Criticism of GM Foods…

Human health risks
–
–
–
–
–

Allergenicity
We already have allergies to peanuts and other foods…
Introducing gene may create more allergies
Unknown effects on human health
However, proposal to introduce a gene from Brazil nuts
into Soyabeans was abandoned
On the whole, with the exception of possible
allergenicity, scientists believe that GM foods do
not present a risk to human health!
Criticism of GM Foods

Economic concerns
– Lengthy and costly process
– May be patented


Monsanto, Novartis, Dow, DuPont hold patents for GM crops
Make substantial profit by exporting it to EMs
– Farmers from developing countries/EM cannot afford
– More gap between rich and poor

Other invention  discouraged/stopped
– Suicide gene technology


Only one growing per season
Next time would produce sterile seeds that do not germinate
Governments and GM Foods…
2009: 25 countries
Governments and GM Foods



Europe: Anti-GM protests (Austria, France, Hungary)
Japan: GM testing is mandatory. Customers for organic
USA: FDA  GM foods are substantially equivalent to
natural food, so not subject to FDA regulations
– GRAS  Generally Recognized As Safe


India: No policy yet  for GM  ↓ poverty
Brazil: Some states have banned GM crops
– ↑Smuggle to compete with grain-exporting countries

Africa: EU opposes the use of GM in Africa
– S. Africa, Sudan, Zimbabwe have GM laws; Kenya Act  2009

Argentina: Indifferent

New Zealand: NO GM Foods grown here!
GM Food Labeling


No need to label  same wrt to nutrition
Europe and Japan  Mandatory
– 1% contamination of unmodified products with GM
foods
– Consumers have the right the know the information
– Let consumers decide  but no choice
– Reduced sales, so processors do not sell GM foods
– EU has disguised policy of protectionism

Canada and US  Voluntary
– Mandatory for Non-GM foods
– Let consumers decide  more choices
Homework Assignment

How do you feel about GM foods? Are
they beneficial or harmful?
 Compare and contrast articles of your choice
 Write a short report on your views about GM
foods.
Possible Risks
of GM Foods


Insects might
develop resistance
to pesticideproducing GM crops
Herbicide-tolerant
crops may crosspollinate weeds,
resulting in
"superweeds"
Possible Risks
for GM Foods


Certain gene
products may be
allergens, thus
causing harm to
human health
There may be
unintended harm to
wildlife and
beneficial insects
Photo courtesy of T. W. Davies, Cal. Acad. of Sciences.