Transcript Luncheon

GMOs 101: Fact vs. Fiction
Dr. Anita Brûlé-Babel
Department of Plant Science
One University. Many Futures.
Outline
• Why it is hard to get clear information on
GMOs
• Definitions
• Comparison of methods
• Examples of products being produced
• Issues
• Labelling
• Moving Forward
Why the confusion?
• Issues are complex and confused with other issues
• Polarized view points
• Nature of news reporting and information sources
– Fear mongering & sensationalism
– Sound-bites
– Social media
– Celebrity effect
– Unqualified “experts”
– Scientific literature inaccessible to general public
• Lack of trust
Definition of “Trait”
• A distinguishing quality or characteristic
that is inherited
– Examples
•
•
•
•
Seed size
Flower color
Height
Herbicide resistance
What is a Genetically Modified
Organism?
Canadian Food Inspection Agency
definition:
“An organism, such as a plant, animal or
bacterium, is considered genetically
modified if its genetic material has been
altered through any method, including
conventional breeding. A "GMO" is a
genetically modified organism.”
http://www.inspection.gc.ca/plants/plants-with-novel-traits/general-public/overview/eng/1337827503752/1337827590597
Genetically Engineered/
Transgenic Organism
An organism, such as a plant, animal or
bacterium that has been modified using
techniques that permit transfer or removal of
genes through non-sexual techniques such
as recombinant DNA technologies.
This is what is being regulated in most
countries. For clarity the rest of this
discussion will be based on this definition.
Generating new combinations
(recombinants)
is the basis of plant breeding!!!
Parent 1
Yellow Smooth Seed
(Homozygous)
X
YYWW
F1
Yellow Smooth Seed
(Heterozygous)
yyww
Parent 2
Green Wrinkled Seed
(Homozygous)
YyWw
Self Pollinate
F2
Segregation
YW
Yw
yW
yw
YW
YYWW
YYWw
YyWW
YyWw
Yw
YYWw
YYww
YywW
Yyww
yW
yYWW
YyWw
yyWW
yyWw
yw
yYwW
yYww
yywW
yyww
9 Yellow Smooth:3 Yellow Wrinkled:3 Smooth Green:1 Green Wrinkled
How does GE differ from
traditional plant breeding?
Traditional Breeding
Genetic Engineering
• Restricted to gene pool of
closely related species
• Interspecific crosses can lead
to relatively large blocks of
DNA being transferred
between species (> one
hundred thousand to millions
of base pairs)
• Produces new combinations of
existing traits
• Not restricted to related
species
• Foreign DNA (if used)
relatively small (a few hundred
to tens of thousands of base
pairs)
• Produces traits that may not
exist within the species
Human genome – 3 Billion base pairs
Wheat genome – 15 Billion base pairs
Rice genome - 0.4 Billion base pairs
Transgenic Plant Chromosome
Cointegrate Ti plasmid
Tobacco-plant
Cell
Transgenic
Tobacco
Plant
Transformed Cell
Plantlet
Cultured Cells
Images from Griffin et al. 1996. An Introduction to Genetic Analysis. 6th Edition.
Many Genetic Engineering Techniques
Old Technology
New Technology
• Required use of bacterial
or viral vectors, or gene
gun
• Needed a selectable
marker to identify
transformed cells
• Can target specific gene
sequences
– Antibiotic resistance or
herbicide resistance
markers common
• Methods not very precise
– Required a lot of follow-up
testing
– Make a single nucleotide
change or delete or insert
specific sequence
• Do not require selectable
markers – high throughput sequencing available
• Does not always involve
transfer of genes from
another organism
• Can be tissue specific
Regulatory Oversight Important
• Varies between countries
– Canada – regulates novel traits regardless of
technology used to introduce the novel trait
– USA – regulates the technology used to
introduce the trait, not the trait – gene editing
will not likely be regulated
– EU - regulates the technology used to
introduce the trait, not the trait – position on
gene editing unclear
Detection of gene editing products will be difficult
if industry does not provide specific information.
What is current situation?
Genetically Engineered Crops
• Main crops in commercial production are
soybean, cotton, corn, canola, papaya,
summer squash and alfalfa
• Approvals made for many other crops but
no significant commercialization has
occurred (e.g. tomato, flax, rice)
• Large number of experimental materials
have been developed with no intent for
commercial release
Types of Engineered Traits
Crop
Traits
Corn
Herbicide resistance, insect resistance, male sterility for hybrid
seed production, high lysine, thermostable alpha amylase
Soybean
Herbicide resistance, insect resistance, oil quality modifications
Cotton
Herbicide resistance, insect resistance
Canola
Herbicide resistance
Papaya
Virus resistance
Squash
Virus resistance
Alfalfa
Herbicide resistance, reduced lignin
Majority of these traits protect yield, with a few
modifications to quality/nutritional factors
Herbicide Tolerant Crops
Canola
Glyphosate (Roundup™)
Glufosinate (Liberty™)
Imidazolinone
Bromoxynil
Impact of HTC
• Better weed control “in crop”
– Protects yield
– Reduces potential contaminants
• More complex weed control and crop
rotation
• Initially reduced herbicide “load”
– Volunteer control can be an issue
• Gene flow
• Herbicide resistant weeds
Herbicide Resistant Weeds
• Existed long before introduction of GE
crops
• Natural variation in weed populations
exists
• Application of herbicide applies selection
pressure that allows resistant variants to
survive and reproduce
• Application of repeated intense selection
pressure leads to establishment of
herbicide resistant weed populations
Heavy selection
pressure leads to
changes in population
characteristics
 Some biotypes of barnyard
grass have developed
biotypes that resemble the
crop plant (resistant to hand
weeding)
 Plant on left is rice
 Plant in middle is a
barnyard grass mimic –
differs by absence of
ligule
 Plant on right is
barnyard grass that is
easy to differentiate
from rice
Barrett, S. 1987. Mimicry in
Plants. Scientific American
257:76-83.
33 resistant weed species
What is the real problem?
Glyphosate (Round-Up™)
Glufosinate (Liberty™)
• Herbicide important for no-till
• Use limited until GE crop
system prior to the GE crop
introduced
• GE allowed use of herbicide in
• GE allowed use of herbicide in
crop
crop
• Applied multiple times in
• Mainly used with GE crop
season = increased selection
• Added new tool to weed
pressure
control
• Multiple glyphosate resistant
• Improved rotational options =
crops means no rotation of
reduced selection pressure for
herbicide = increase selection
other herbicides
pressure
• 2 resistant weed species
• 23 resistant weed species
(2012)GE can enhance
When
implemented
correctly,
(2012)
crop production and reduce potential for
development of herbicide resistant weeds.
Insect Resistant Crops
• Bt toxin
– Produced by Bacillus
thuringiensis
– Effective against
specific insects (e.g.
Colorado potato beetle,
European corn borer)
– Not toxic to humans or
animals
– Considered
environmentally friendly
http://faculty.evansville.edu/ck6/bstud/potato.html
http://www.ent.iastate.edu/imagegal/lepidoptera/ecb/46ecblarva.html
Insect Resistance
• Reduces application of more
toxic pesticides
• Protects non-target insects
including beneficial insects
• Non-adopters benefit from
reduced insect populations
• Evidence of reduced levels of
mycotoxins in food and feed
• Potential for development of
insect resistance
– Concern for organic
farmers that use the Bt
biocide (resistance to
biocide observed before
GE crop introduction)
• Could be tissue specific
Can have positive effects
for environment and
human health.
Gene Flow
• Genes can move between GE and non-GE crops of the
same species
– Reproductive biology of the crop affects how much
– Genes move between crops regardless of whether
they are GE or not (reason for seed regulations)
• Spread to wild relatives – possible if present in same
area
– Impact depends on trait
• If trait has no selective advantage it can remain in population
at low levels
– Few wild relatives of many major crops
• GE crops can become invasive if the trait has a selective
advantage
– Part of regulatory evaluation
Food Safety
• Regulatory system evaluates GE crops for food
safety based on concept of “substantial
equivalence”
– Composition, nutrition, toxins, allergens, etc.
• North American vs. European concepts of safety
– N.A. – “acceptable risk” – considered relative
to non-GE equivalent
– European – “absence of risk” – Impossible to
prove
• Traditional foods were never tested for safety
– Selective breeding/domestication has made many
crops safer (e.g. Canola)
Influence of GE Crops on
Human Health
• Several large-scale reviews published
– Genetically Engineered Crops: Experiences and
Prospects - http://www.nap.edu/23395
– A Decade of EU-Funded GMO Research (2001-2010)
https://ec.europa.eu/research/biosociety/pdf/a_decad
e_of_eu-funded_gmo_research.pdf
– An Overview of the Last 10 Years of Genetically
Engineered Crop Safety Research – Critical Reviews
in Biotechnology 2013 DOI:
10.3109/07388551.2013.823595
Study Conclusions
• No credible evidence that GE crops/foods
developed to date pose a threat to human
health
– Reviewed original peer-reviewed literature
– Evaluated quality of the research including
experimental design
• Potential for harm exists if the regulatory
system does not do its job
– Trait-specific, not technology-specific
Comparison of Cancer Rates
World Cancer Research Fund International
Rank
1
2
3
4
5
6
7
8
9
10
11
12
Age-Standardised Rate
per 100,000 (World)
Denmark
338.1
France (metropolitan)
324.6
Australia
323.0
Belgium
321.1
Norway
318.3
United States of America
318.0
Ireland
307.9
Korea, Republic of
307.8
The Netherlands
304.8
New Caledonia
297.9
Slovenia
296.3
Canada
295.7
Country
http://www.wcrf.org/int/cancer-facts-and-figures
Specific Cancers
• Rates of 14 cancers monitored by country
– Reported 20 countries with highest rates
– Neither USA or Canada had the highest rates
for any of the 14 cancers
– Where USA or Canada ranked within the top
20, there was at least one European country
with higher rates
> 20 years of consuming GE crops in NA has
not resulted in higher cancer rates than EU countries.
http://www.wcrf.org/int/cancer-facts-and-figures
Labelling
• Push for labelling based on assumptions
of potential risk
• Unnecessary if have “substantial
equivalence”
• Form of labelling important
– Must be informative
– Specific gene alterations
may be more important
• Co-existence will require significant added
expense
• Consumers may be duped to pay
http://www.nongmoproject.org/wp-content/
more for products that were
uploads/Non-GMO-Project-Standard.pdf
never GE
http://sustainablepulse.com/wp-content/uploads/201
6/01/campbells-gmo-label-2-644x363.jpg
Many Other Issues
•
•
•
•
•
•
Monoculture
Multi-national control
Seed sovereignty
World hunger
“Natural” or “Organic”
Regulatory inadequacies
and inconsistencies
• General lack of science
literacy
• Associations vs cause
and effect
http://boingboing.net/2013/01/01/correlation-between-autism-dia.html
Moving Forward
• Technology is changing rapidly
• Regulatory systems are not keeping up
– Lack of consistent international standards causes
further confusion and adds cost
– Risks need to be assessed on a case-by-case basis
• Separate out the issues
• Potential to improve environmental sustainability,
agricultural productivity, and human health
• One of many tools available to “feed the world”
• Decisions should be based on sound science
– Information sources are critical
• Public good should prevail over corporate good
– Proper evaluation of products is crucial
Final Thoughts
• GE technologies have great potential for
both good and bad
• Require strong regulatory system to
evaluate
• Risk/benefit ratio needs to be properly
assessed
• Alternatives should be part of evaluation
• Accessibility of scientifically sound
information critical