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gooseliverBiotechnology

Oct 22, 2013 (3 years and 7 months ago)

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Laurie Mets

Molecular Genetics and
Cell Biology

The University of Chicago

Fermi Lab, March 16, 2002

Genetic
Engineering and
Food

How can we understand
the impact of science on
what we eat?


Good Food

at a
Good Price


Nutritional


Energy (calories)


Essential nutrients


Appealing


Flavor


Appearance


Not harmful


Highly productive
agriculture

Genetic Engineering

impacts each of these

properties of plants

(and animals)

What is “Genetic Engineering?”


“Genetic engineering focuses on the manipulation
(blocking, adding, or scrambling) of the genetic
material (the DNA) inside the cells of living
organisms to block or add desired traits.”
www.wholefoodsmarket.com


Modification of the genetic makeup of organisms
by man


Cross
-
breeding and progeny selection


Plant A fertilized with pollen from plant B


Molecular genetic engineering


Enabling technology
-

not

intrinsically harmful;
not

intrinsically beneficial

Genetic Engineering is an
Ancient Art


Darwin


variation is much higher in domesticated
species than in wild species


Braidwood


time and place of domestication can
be traced to location of increased variation


Bruce D. Smith


times and sites of domestication
correspond to the origins of organized civilizations


Variations under domestication represent changes
in the genetic composition of the organisms
associated with man’s activities


Best Invention of the Millenium


-

NY Times Magazine, 4/19/99

“How the bean saved
civilization”



-

Umberto Eco

Prof of Semiotics, Univ. of Bologna

Examples of engineered species


Wheat (
Triticum aestivum
)
-

a man
-
made species


Corn (
Zea mays
)
-

derived from teosinte


Soybeans (
Glycine max
)
-

from
G. soja


Potatoes (
Solanum tuberosum
)
-

wild
varieties are toxic


None of the food varieties can grow
without help from man

The Development of Genetic
Engineering Techniques


Darwin
-

models for understanding the role of
selection


Mendel
-

mathematical models for predicting the
outcome of cross
-
breeding


Beadle (et al)
-

how genes determine the chemical
composition of organisms


Watson & Crick
-

general model for DNA
structure


Cohen & Boyer


DNA splicing leads to artificial
“transgenic” organisms

Agrobacterium


A soil bacterium that generates transgenic plants


Transfers some of its genes to the plant


Causes “gall” growths and forces the plant to make
nutrients for it


Use by human molecular genetic engineers:


genes that the bacterium transfers are replaced by others


e.g. BT toxin for pest resistance; herbicide degrading
enzymes for herbicide resistance; enzymes to alter fatty
acid composition or add nutrients (Golden rice)


Host range has been modified for engineering monocot
crops like rice and corn

Virtual Engineering Projects


What property of an organism would you
like to change?


How might that property be controlled by
genes?


What specific steps must be taken to
accomplish the engineering?


Assessment: what are the social impacts


both intended and unintended?

Molecular anatomy of a gene

Unicellular
organism

Multicellular
organism

“From Alchemy to Algeny”

“The very thought of recombining living material
into an infinite number of new combinations is so
extraordinary that the human mind is barely able to
grasp the immensity of the transition at hand”

Jeremy Rifkin,
The Biotech Century

Like the theories underlying alchemy, this
analysis is based upon a faulty scientific model.


What can be engineered is limited by physical and
genetic realities.

Science provides
tools and models


Valuation requires
social and political
processes







What should be genetically
engineered?



Why should it be engineered?



Who should be involved in the
discussion?



How should the discussion be
conducted?

Problem:

The pace of change enabled by
modern genetic engineering is
outstripping the ability of cultural
traditions and institutions to
assist in the evaluation of foods

“Public aceptance of foods [from
transgenic plants] ultimately depends
on the credibility of the testing and
regulatory process…”

Dr. Perry Adkisson

April 5, 2000

in introducing public release of the
National Research Council report on
“Genetically Modified Pest
-
Protected
Plants: Science and Regulation”

How does genetic engineering
affect agricultural practice?


Traditional cross
-
breeding for commodity
markets is a numbers game that will always
be dominated by the largest players


Engineering of added value traits should
create specialty niche products, subdividing
commodity markets and creating
opportunities for smaller scale players

Why is the organic farming industry
opposed to “Genetic Engineering?”


Organic farming accesses a niche market of
consumers who want to avoid potential
exposure to agricultural chemicals


Genetic methods that could obviate the use
of chemicals in traditional agriculture
represent a threat to that niche

From www.wholefoodsmarket.com

“Unintended Consequences of Agricultural Biotechnology”

Antibiotic resistance.

The use of antibiotic resistant “marker”
genes risks the transfer of antibiotic resistance into humans and
the environment, diminishing the effectiveness of the
antibiotics.


Antibiotics in common use for marker selection:

G418;

Kanamycin

From www.wholefoodsmarket.com

“Unintended Consequences of Agricultural Biotechnology”

Allergies.

The effect known as antiidiotope allergen.
Cummins in “
Genetic Engineered Foods and Allergenicity”
states that “When an antibody is made against an antigen
(allergen) there is an antibody made against the antibody
(antiidiotope antibody). Most genetically engineered crops
have genes for antibiotic tolerance, which produce enzymes
that match an allergenic antibiotic. The enzymes will produce
antibodies that are allergens. Thus most genetically engineered
crops are likely to be allergenic to people sensitive to
antibiotics.”

Antibiotics in common use for marker selection:

G418;

Kanamycin

What lies in the future?


Modern gene transfer engineering makes
smaller, more defined changes than
traditional cross
-
breeding methods


Genomic approaches to marker
-
assisted
breeding promise to make engineering by
cross
-
breeding more efficient and precise

Comparative Physical Mapping

Microbial Community Assessment

with Raj Sinha, Chicago State Univ.

Vancomycin resistant enterococci from
produce
-

lateral transfer or selected strains?


Civilization itself
depends upon
genetic engineering


Techniques are
becoming more
powerful and technical
outcomes more
predictable


Use of engineering
requires thought