2008_Genetic_engineering_in_foods

2008_Genetic_engineering_in_foods - Genetic Engineering in...

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Genetic Engineering in the Food Supply General objectives of genetic engineering related to foods: Increase supply , variety, or quality of foods by means difficult or impossible to achieve via conventional plant or animal breeding techniques Modify microorganisms to assist in improving food safety or producing products useful in food production, processing , or waste management
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Specific goals of genetic manipulation: Improve quality of foods Appearance Texture, taste Nutritional value Increase yields of plant or animal foods Increase pest resistance Increase pesticide / herbicide tolerance of plants Increase drought tolerance Decrease fat content (meats) Reduce waste processing costs
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Genetic manipulation : Altering the genetic composition of an organism for a prescribed purpose     Cross breeding Genetic engineering   Cross-breeding : > 10,000 yrs old, beginning with efforts to domesticate wild plants, animals Selects beneficial inheritable traits from naturally- occurring genetic diversity Used successfully in both plant & animal foods
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Genetic Inheritance Genotype : Gene composition of an organism, totality of potential traits Phenotype : Expressed traits of an organism   e.g. tomato : color texture (hard vs soft) shape taste (glucose, sucrose, acid content) germination time, ripening time   Phenotype is determined by the extent to which each gene is expressed (may vary over time within an individual organism)
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Cross-breeding relies on sexual reproduction : female gene donor male gene donor duplicate chromosome set duplicate chromosome set F 1 generation Cross-breeding approach: Selects male, female donors in attempt to produce F 1 progeny with specific desirable traits
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Limitations of cross-breeding : a. Can access only the diversity within closely -related species than can be cross-bred b. Success depends on those phenomena that regulate the inheritance of genetic trails c. Undesirable traits can be inherited along with specific desirable traits (not selective) d. Slow--often 5-10 yrs required for success; limited by generation time of species
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Genetic engineering (recombinant DNA technology): Seeks to create new genotypes by selective modification of the genome Potentially: * add new gene(s) from a different species * selectively express genes in tissues that do not normally express that gene * inactivate genes (prevent expression) * delete genes Transgenic organism: Organism containing a foreign gene (a “transgene) obtained from another species Currently : Several examples of transgenic plant foods No transgenic animal foods
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Gene structure l
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DNA (chromosome) mRNA Protein Transcription Translation Gene transcription and translation
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This note was uploaded on 03/11/2010 for the course NS 3450 at Cornell University (Engineering School).

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2008_Genetic_engineering_in_foods - Genetic Engineering in...

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