Transcript GMOD: Identifying Genetically Modified Organisms in Food

GMOD:
Identifying Genetically
Modified Organisms in Food
Are we eating genetically altered foods?
Objectives
• To identify the presence of
genetically modified organisms
(GMOS) in foods purchased from
the shelves of local grocery stores.
•
To discuss ethical issues
associated with GMOs and their
use in food.
What are GMOs?
• GMO= Genetically Modified Organism
• GMOs contain genetic material (DNA) that
has been altered or modified through a
method that does not occur in nature.
• Often the modification is designed to
introduce a new or altered characteristic
to the modified organism.
• GMOs are becoming increasingly common
among agriculturally important plants.
Why have GMOs been developed?
• With the current technology of
incorporating DNA from one organism
into another organism, new breeds
can be developed faster with new,
advantageous traits, such as insect
resistance, drought tolerance or the
ability to produce fruit in colder
climates.
Examples of GMOs
Bt Cotton
• Bt cotton planted from
1996 to 1998 is
estimated to have
yielded 5% more.
• Bt cotton requires less
foliar spray than acres
with no Bt cotton
• Use of Bt cotton has
significantly decreased
the cost of insecticides
Examples of GMOs
Roundup® Ready Crops
• Yield increases in
some crops, due to a
better crop safety and
less weed competition.
• Efficient control of
tough weeds
• Competitive, costeffective weed control
programs
Supporters of GMO
• Supporters of genetic modification argue
that the genetic changes improve the
nutrient content, handling conditions or
hardiness of the food and will result in
higher yields to increase the availability
of food to meet the demands of growing
world population.
Controversy over GMOs
A number of concerns
have been raised
regarding genetically
modified foods. These
include worries about
the safety of human
health and the health of
the environment.
Controversial Topics with GMOs
• Some fear that
consuming genetically
modified foods may
expose an individual
to proteins that the
immune system may
not recognize,
triggering an allergic
reaction.
Could GMOs be responsible for the
increase in allergies & automimmune
disorders?
LOOK AT THESE STATISTICS:
•
In the last 20 years, there has been an epidemic increase in allergies,
asthma, auto-immune disorders, ADHD, and autism. Today, it is estimated
that 20% of American children have allergies, and that there has been a:
• 400% increase in FOOD ALLERGIES
• 300% increase in ASTHMA, with a 56% increase in asthma deaths
• 400% increase in ADHD
• 1,500 and 6,000% increase in AUTISM.
More Controversy
• GMOs are present in many products
available on supermarket shelves and
produce bins today.
• Yet, many people do not realize they are
eating GMOs.
• This is partially because, in the United
States, products containing GMOs do not
need to be labeled, and those which are
made from less than 5% GMOs can be
labeled “GMO-free.”
More Controversy continued
• Genetically modified crops
become the standard in
food production, then
developing nations may
become heavily dependent
upon industrialized nations
to supply the majority of the
seeds.
• Others question the ethics of
consuming animal genes in
plant materials and the
effect of foreign DNA on
animal stress and health.
How are GM plants made?
1. The gene of interest is first placed within a
small carrier fragment of DNA called a
vector.
2. The vector is introduced into a single plant
cell. In the laboratory, the cell is allowed to
develop into a fully-grown plant.
3. Under the appropriate conditions, the new
gene begins to function, leading to the
appearance of the modified trait within the
plant.
How are GM plants made?
• Many different genetically modified crops
use an identical type of vector.
• In our lab activity, we will test different foods
to see if they have been genetically modified
foods based on detecting this common
vector.
• This detection method will be able to identify
most forms of GM corn and soybean.
Why test for the presence of GMOs
• The United States and Europe have
different policies on labels required
for food products containing GMOs.
As mentioned, in the United States,
food products containing GMOs are not
required to be labeled.
• In Europe, they will not accept an
imported crop unless it is 0.9% GM or
less.
Why test for the presence of GMOs
In other countries, such as Mexico,
GMOs are prohibited as a means of
protecting the country’s agricultural
heritage. As such, it is important to
the farmer, the importer and the
exporter to be able to test crops to
determine whether they do or do not
contain GMOs.
How will we test for the presence of
GMOs?
• There are 2 common ways in which the
presence of GM crops is currently
detected.
• ELISA (Enzyme Linked ImmunoSorbent
Assay).
• The other is based on a process called
PCR (Polymerase Chain Reaction)
This is what we will use in LAB!!
PCR- Polymerase Chain Rxn
• PCR is laboratory version
of DNA replication.
• A special machine called
a thermal cycler makes
this technology possible.
• PCR is often referred to
as a “molecular copy
machine.”
What are we looking for?
• After isolating DNA from samples of food,
you will use PCR to amplify two genes.
• The first gene, known as NPTII, is part of
the vector used to create many GMOs.
• The second gene is a 16S ribosomal gene
associated with plant chloroplast DNA.
Because this gene is present in all plants,
it serves as a control to see if your DNA
extraction and PCR processes were
successful.
How do we determine if our food is
a GMO?
• The amplified PCR
products will be separated
and visualized through gel
electrophoresis.
• Analyze the gel for the
presence of the NPTII
gene and the 16S
ribosomal marker. If both
show up, then your
product does in fact
contain GM food crops.