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Brian EllisBiotechnology Laboratory - UBCMay 02, 2001
Health Canada is mandatedto ensure that the Canadianpublic is not put at risk fromfood or health care products
HC must assess all novel foods
From other geographic regions
From new manufacturing processes
Origins of Novel Foods
From plant breeding
History of safe human consumption?
Contains known toxicants?
Assessment of Novel Foods
Nutritional value altered?
Plant Breeding
Development and evaluationof new genotypes
1. Create variation
2. Select
3. Repeat….
1. creates new allelic combinations within a species genome
2. samples mutational / recombinational changes
Classical Plant Breeding
Progeny Evaluation
SEXUAL CROSSES
Existing varieties
Distantly related speciesInduced mutants
Closely-related species
LandracesSelections
products of plant breedingare generally regarded
as safe
“barley is barley is barley”
• long history• highly selected
How do GMO genotypes fit within this model?
derived from known (GRAS)germplasm
very few new genetic elementsadded to parental variety
Do a comprehensive (and slowand expensive) food safety assessment ?
The conundrum….
…or assume that the genetic background is benign,
The conundrum….
assess traits directly related to the transgene, and
establish “substantial equivalence”
comparison of the GMO productwith the conventional
Substantial Equivalence
assesses differences between them
focuses on the transgene and on hallmarks of conventional genotype
Strengths
Substantial Equivalence
Focuses on most likely impacts
Uses established methodologies
Weaknesses
Substantial Equivalence
Assumes linear responses to genetic change
Uses targeted rather than global analytical methodologies
Differential gene expression in the Arabidopsis hypocotyl
wildtypeein 4 mutant
S. Regan, Carleton U.
Cellular systems are highly integrated at all levels
PLEIOTROPY
Plant metabolism is extraordinarilyplastic - adapted to creation of new metabolites
Fiehn et al, Nature Biotechnology (2000)
Metabolic shifts induced by single-gene changes
in Arabidopsis thalianadgd-1
sdd-1
Assume that pleiotropic effectswill occur in GMO organisms
Strengthening Substantial Equivalence
Develop and adopt global profiling methodologies
Focus safety assessment on revealed differences