This document discusses the biosafety of genetically modified crops. It outlines the approach taken to assess safety, including potential risks like toxicity, allergenicity, antibiotic resistance, and gene flow. The regulatory framework for genetically modified crops in India is also mentioned. Specific concerns discussed include Brazil nut allergy in soybean, use of antibiotic resistance marker genes, consumption of foreign DNA, and effects on biodiversity and target species. Strategies to prevent unwanted gene flow are described.
1. Biosafety of Genetically Modified CropsBiosafety of Genetically Modified Crops
Ekatpure Sachin Chandrakant
2. 2
Biosafety of GM Crops
Policies and procedure adopted to ensure environmental
safety during the course of development and
commercialization of genetically modified organism
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6. 6
Risk of toxicity/ allergineicity
Addition of new genetic material
may activate toxic pathways
Appearance of novel metabolites
Introduction of new protein
Non immunogenic protein could
become immunogenic
6(Kaeppler, 2000)
7. Brazil nut allergy in soybean
A well-known case of a GM soybean
allergy
2S albumin gene from Brazil nut to
soybean (enhanced methionine)
(Julie et al,1996)
Allergen transferred unintentionally
from Brazil nut to GM soybean
Investigations with GM soybean
revealed immune reactions in people
with Brazil nut allergies 41
8. 8
Antibiotic resistance
Marker gene could induce antibiotic resistance
Would reduce effectiveness of antibiotics to fight diseases
Conditions for HGT (horizontal gene transfer) :
DNA must be free from the cells
Bacterial recipient must be competent
Integration depends on sequence homology
Acid environment of human stomach
HGT of nptII gene can occur 1 in 10 billion
Specificity of promoter
8(Redenbaugh et al,1994)
9. Eating of foreign DNA
DNA present in all living things and
eaten by humans with every meal
Broken down during digestion process
Small amount absorbed in blood stream
or excreted
According to WHO amount of DNA
ingested- 0.1 to 1 g/day (novel DNA
represents 0.0001%)
(Chawla , 2009) 9
10. Use of promoters of virus origin
Concerns expressed regarding human health
eg. 35S promoter of CaMV
It might be harmful if it invades human cells and turns
on certain genes
Probability is very low and no such report so far
10
11. Changes in nutrition level
Accidental changes in nutritional component of GM crop
Report spread in 1997 that Roundup Ready soybean
produces large quantities of phytoestrogen (causes breast
cancer) after glyphosate spray
Investigation revealed no such increase
11
(SAG report, 1997)
12. 12
Gene Flow
Accidental cross between GM
plant and traditional local varieties
or weedy relative
Contaminate local variety with
transgene (eg.superweeds)
Ryegrass highly resistant to
glyphosate already found in
Austrailia
12
(Gaur et al.,2010)
13. 13
Report on corn contaminated by GM genes
in Mexico
David Quist and Ignacio Chapela in Nov 2001 reported
transgenic DNA construct 35s promoter sequence found
in Creole maize at Oaxacan state of Mexico
CIMMYT amplified 28 accessions from Oaxacan
landraces with CaMV 35s promoter primer
Samples did not show presence of 35s promoter
13(CIMMYT report,2001)
14. Strategies to prevent gene flow
Isolation zone
Trap crop
Male sterility
Chloroplast
transformation
Clean gene technology
- Devoid of vegetation
- Use of non-transgenic variety
- Inactive pollens
- Gene construct introduced into
chloroplast
- Markerless GM
14(Chawla,2009)
15. 15
Resistance of target species
Insect/ virus population rapidly adapt to environmental
pressure
Development of new strains
Gene pyramiding - Best solution
15
16. 16
Impact on biodiversity
Reduction in genetic diversity by development and global
spread of improved varieties
Sustainable agriculture depends on mixed cropping and
crop rotation
Not unique to GM but is relevant to all improved varieties
Bt protein is highly unstable rapidly degraded in stomach
juices of vertebrates and in soil
16
17. Monarch butterfly incidence
Monarch butterfly catterpillers died when fed on Bt
maize pollen
It was a lab experiment
Butterfly fed only on Bt maize pollen
For toxic effect of Bt protein it should meet specific dose
requirement
In nature it is not possible to meet that dose level
17(Losey et al,1999)
18. Warangal Attempt
Farmers of Warangal district of Andhra Pradesh reported cattle
and sheep dying on consuming Bt cotton plants
No one has so far conclusively proved that Bt protein in the Bt
cotton plants was the real culprit
Why do the cattle die eating Bt cotton only in the Telngana
region of Andhra Pradesh ?
Clearly a mischievous and cheap attempt to denigrate and
discredit the Bt technology
(Rao, 2007)
58
19. Ethical issues
Unacceptable intervention in “God’s creation
violating barriers in natural world”
Objections to consuming animal genes in plants
and vice-versa
Demand for GM and Non GM food labelling
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