Transcript - Catalyst

Genetic modification and GMOs
This is controversial!
• Purpose is to give you the basis to acquire
information and make informed decisions
Four major approaches to genetic
modification
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Selective breeding
Hybridization
Polyploidy
Gene insertion
Selective breeding
• Choosing parents with desirable traits
– In animals the results are called “breeds”
– In plants they are called “varieties” or “cultivars”
• Charles Darwin, in Origin of Species begins
with examining selective breeding and his
term “natural selection” as his basis for
evolution is derived from the comparison of
the selective pressures in nature compared to
a domestic breeder
Selective Breeding
Techniques in selective breeding
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Choosing parents
Finding new natural varieties to breed from
Artificial insemination
Generating new mutations
– Exposure to X-rays or chemical agents that cause
mutations. Most will be bad but sometimes a
useful new trait pops up
Pure breeds vs hybrids
• In many cases selective breeding strives to
produce a pure breed – that is all the offspring
will have the same traits
– Pure breeds tend to be homozygous (have the same
gene) at most loci
• Hybrids are individuals who result from the cross
from two different breeds
• Hybrids crops often outperform pure breeds in
yield etc.
– This is called hybrid vigor, heterosis, or outbreeding
enhancement
Hybrid corn
• Invented in the UK in late 19th century
• Commercial technology was perfected in the US
during WW I, and now involves crossing two
inbred lines.
• Almost all corn planted in the developed world is
hybrid corn
• Because it requires crosses, farmers cannot use
their own seed and replant – a major
“commercial” advantage of hybrid varieties for
seed producers
Polyploid oysters
• By subjecting oysters to thermal or chemical
stress early in development, you can prevent
meioisis, that is normal chromosomal
replication. Thus you have oysters with more
chromosomes than normal.
• This means they cannot reproduce and won’t
devote energy to reproduction and instead
allocate the energy to flesh that we eat
The patent for polyploid oysters
GMOs
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The nature of genetic modification
The controversy
The risks
The data: how risky, what benefit
The current state
Modern Biotechnology
The Cartagena Protocol on Biosafety defines “modern
biotechnology” more narrowly as the application of:
(a) In vitro nucleic acid techniques, including recombinant
deoxyribonucleic acid (DNA) and direct injection of
nucleic acid into cells or organelles, or
(b) Fusion of cells beyond the taxonomic family, that
overcome natural physiological reproductive or
recombination barriers and that are not techniques used
in traditional breeding and selection.
The most common GMO crops
• Insertion of gene from bacillus thurigensis
that kills lepidoptera (moths and butterflies)
called BT corn or BT soybeans
• Insertion of a gene that provides resistance to
the common herbicide “Roundup” (glyphosate
and gluphosinate) so that crops can be
sprayed with roundup and the weeds will be
killed
• Vitamin enriched corn (Africa)
BT corn
No till farming
No till farming
Class Poll
• Assume there was a ballot referendum on
prohibiting the sale and use of Genetically
Modified Organisms
• Who would vote in favor of the ban GMOs
• Who would vote against GMO
The controversy
Frankenfish
The concerns and risks
• pollen from the GMO may carry to a non-GMO crop, thus
introducing the novel gene into a conventional crop ,
• pollen from a herbicide resistant GMO may cross with a
compatible weed and introduce resistance in the weed,
• insects might develop resistance to insecticides made in GMO
plants (e.g. Bt cotton),
• harm might result to soil biota, thus harming nutrient cycling,
• the GMO might have a poor nutritional profile or be poorly
digested
• the GMO might make a toxin, allergen or teratogen.
• Furthers corporate control over the food supply
BT corn concerns
The European Commission Directorate-General for
Research and Innovation 2010 report on GMOs noted that
"The main conclusion to be drawn from the efforts of
more than 130 research projects, covering a period of
more than 25 years of research, and involving more than
500 independent research groups, is that biotechnology,
and in particular GMOs, are not per se more risky than e.g.
conventional plant breeding technologies." A 2008 review
published by the Royal Society of Medicine noted that GM
foods have been eaten by millions of people worldwide for
over 15 years, with no reports of ill effects. Similarly a
2004 report from the US National Academies of Sciences
stated: "To date, no adverse health effects attributed to
genetic engineering have been documented in the human
population.”
Use and Benefits
World GMO production 2009
S=soybeans,m=maize (corn),C=cotton,R=rapeseed,SB=sugarbeets
Country
Millions of HA
Crops
U.S.
64
Brazil
21.4
S,M,C
Argentina
21.3
S,M,C
India
8.4
C
Canada
8.2
R,M,S
China
3.7
C several other minor
Paraguay
2.2
S
South Africa
2.1
M,S,C
S,M,C,R,SB others
Aquabounty GMO salmon
Our mission is to play a significant part in “The Blue
Revolution” – bringing together biological sciences
and molecular technology to enable an aquaculture
industry capable of large-scale, efficient, and
environmentally sustainable production of high
quality seafood. Increased growth rates, enhanced
resistance to disease, better food-conversion rates,
manageable breeding cycles, and more efficient use
of aquatic production systems are all important
components of a sustainable aquaculture industry
of the future.
The technology
The fish's rapid growth will be boosted by
the injection of a combination of a growth
gene (GH-coding sequences) from the
Pacific Chinook salmon and genetic
material (the AFP gene) from the ocean
pout - a large, eel-like fish - into the
fertilized eggs of Atlantic salmon, making
the recombined DNA present in cells
throughout the body of the fish. The
Chinook gene promotes the growth to
market size, and the pout gene allows the
fish to grow in the winter as well as the
summer.
Key points in controversy
• Does it increase yields or reduce costs?
• Are there other benefits?
– Less pesticide
– Less need for tilling – lowers erosion
• Is it safe
• Does it lead to consolidation of ag industry
and seed production
Corporate control of food supply
• With hybrid varieties farmers can’t save seed
and replant
• Large corporations control much of the seed
supply
• Many crops can be patented – is food a public
good or private property?
Why so much uncertainty and
controversy
• Numerous parties with agendas
– Industrial groups with financial interest
– NGOs with fixed positions
• Both will look for science to support their
position rather than looking to science to
determine what is true
How to resolve scientific uncertainty
• National Academy of Sciences Reviews
– The premier national science organization does
reviews of important topics
• Government Agency independent science
reviews
• Problems with independent science reviews
– It all depends on who is on the panel
Study Guide
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What is selective breeding?
Choice of parents with desirable traits in order to produce offspring with those traits.
Why do selective breeding programs often try to increase the rate of mutation?
To try to generate new traits that are not found in the existing individuals.
What is hybrid?
A cross between two distinct genetic lines.
Why are hybrids used so much in crop production?
Hybrids often display better characteristics than the two parental strains.
What is hybrid vigor?
The “better” trait displayed by a hybrid compared to its parents.
How does the use of hybrids contribute to the commercialization of seed production?
Hybrids do not breed true, that is you cannot plant hybrid seeds and get the same kind of crop.
Why are polyploidy and other techniques used to prevent some animals from reproducting?
So that the animals allocate their energy to building body mass rather than producing eggs and sperm.
What is the difference between the technology of selective breeding and GMOs?
GMOs largely rely on insertion of DNA in the laboratory whereas selective breeding relies on the choice of parents.
Name two commonly used GMO crops.
BT corn that has the bacillus thurigensis gene that kills moths and butterflies, and “roundup ready” crops that have a gene that gives them immunity to the herbicide roundup.
Name three of the major concerns about the environmental impacts of GMOs.
Pollen from the GMO may carry the novel gene to conventional crops,
pollen from a herbicide resistant crop might introduce the herbicide resistance to weed
insects might develop resistance to the pesticides in the GMO crop such as BT.
harm might result to soil biota, thus harming nutrient cycling,
the GMO might have a poor nutritional profile or be poorly digested
the GMO might make a toxin, allergen or teratogen.
What are the two genes in the GMO atlantic salmon?
A growth gene to make the grow faster and another gene to let them grow year round.
How do GMOs interact with the commercial structure of the food industry?
GMOs are a patentable technology, increasing the control a few large seed companies have over the food supply system.
What is the most highly regarded method for resolving scientific disputes in public policy?
Reviews by the National Academy of Sciences