Biosafety of Genetically Modified Crops Biosafety of Genetically Modified Crops

Ekatpure Sachin Chandrakant

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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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Safety assessment approach for GM crops

335

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Elements of assessment

436

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Regulatory framework in India

537

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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)

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

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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)

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

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

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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

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(SAG report, 1997)

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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

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(Gaur et al.,2010)

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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)

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 GM14(Chawla,2009)

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Resistance of target species

Insect/ virus population rapidly adapt to environmental pressure

Development of new strains

Gene pyramiding - Best solution

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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

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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)

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

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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