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Genetic Engineering
Bioethics
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What is Genetic Engineering?
S basic definition: genetic engineering is the direct manipulation
of an organism's genes.
S Genetic Engineering is useful in many fields including food
production and medicine.
S While it seems promising, there is still a lot that we do not
know about Genetic Engineering.
Gregor Mendel
S Gregor Mendel lived from 1822-
1884 in Brunn, Austria.
S He was an Augustinian Monk
who taught natural science to
high school students.
The “Father” of Genetics
S Mendel was the first person to trace the characteristics of
successive generations of living things.
S Mendel wondered how plants acquired atypical
characteristics.
S Mendel performed experiments on pea plants, mice and
ornamental plants.
Dominance and segregation of traits
S Mendel crossed peas and mice of different varieties.
S Through this experiment Mendel discovered the
phenomena of dominance and segregation.
S Dominance decides which characteristic most often
surfaces; the dominant characteristic overrides the
recessive gene and appears in the organism.
S Segregation of genes decides which genes are inherited
from the parents.
Laws of Heredity
S Heredity factors do not combine; they are passed intact
S Ex= A child of parents with black and red hair would
inherit one of the two colors not a mix of the two.
S Each member of the parental generation transmits half of
its hereditary factors to each offspring
S Different sets of offspring from the same parents receive
different sets of hereditary factors
S Ex= siblings are not identical, their differences come
from the inheritance of different genes from their
parents.
DNA
S Discovered in 1869
S James Watson and Francis Crick discovered that DNA had a
double Helix form.
S Our DNA or genes decide who we are, they decide everything
from our eye color to our shoe size.
DNA Engineering
S We use recombinant DNA to manipulate genes.
S Recombinant DNA is taking DNA from one source and inserting
into another organisms DNA giving that being those
characteristics.
S Ex.= Inserting salmon’s anti-freezing genes into corn to allow it to
survive frost.
Process of DNA Engineering
S 1. Restriction enzymes cut DNA at their base parts causing sticky
ends to form.
S 2. DNA ligase (linker sequences of DNA) are placed on the sticky ends
of the DNA.
S 3. A Plasmid holding foreign DNA is inserted into the DNA and is
connected by the ligase. (sticky end to sticky end)
S 4. The recombinant DNA is inserted into a bacterium which carries
out its function inside the larger organism.
S 5. When the DNA becomes active it directs the body to construct
distinct proteins which carry out the gene’s function.
Examples of Genetic Engineering
Spider Silk
S Creation of artificial spider silk by Nexia, a biotech company
S Spider silk protein created by goats in their milk, then spun
into silk
S However, still not comparable to actual spidersilk
Insulin
S Insulin—originally isolated from
cows and pigs
S 1982 – Humulin, a biosynthetic
human insulin
S Attempting to optimize insulin
production by expressing them in
different things
S Insert human insulin gene
into bacteria
Penicillin
S Directed evolution
of penicillin strains
S Inserted genes to
make
erythromycin
(penicillin
substitute) into E
Coli, which totally
worked
Why do weGenetically Engineer
Foods?
S Biotechnology is needed to feed the growing population of the
world, especially the Third World.
S Reduced chemical inputs, which will be good for the
environment.
S Genetic Engineering creates better yields in foods by giving
them:
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Pest resistance
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Herbicide tolerance
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Disease resistance
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Cold/drought tolerance
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More nutrition
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Ability to replenish the soil they were grown in.
Engineered food-process
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Biochemical ‘scissors’ called restriction enzymes are used to cut the strings of DNA in
different places and select the required genes. These genes are usually then inserted
into circular pieces of DNA found in bacteria. The bacteria reproduce rapidly and
within a short time thousands of identical copies can be made of the ‘new’ gene.
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There are now two principal methods that can be used to force the ‘new’ gene into
the DNA of the plant that is to be engineered. A ‘ferry’ is made with a piece of genetic
material taken from a virus or a bacterium. This is used to infect the plant and in doing
so smuggle the ‘new’ gene into the plant’s own DNA. Or, the genes are coated onto
large numbers of tiny gold pellets which are fired with a special gun into a layer of cells
taken from the recipient organism, with any luck finding a hit somewhere in the DNA
in the nucleus of the cells.
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Genetically engineered animals and fish are produced by microinjection. Fertilized
eggs are injected with new genes which will, in some cases, enter the chromosomes
and be incorporated into the animal’s own DNA. Because the techniques used to
transfer genes have a low success rate, the scientists need to be able to find out which
of the cells have taken up the new DNA. So, before the gene is transferred, a ‘marker
gene’ is attached which codes for resistance to an antibiotic.
Genetic Engineered
Foods: Fears
S"Human health effects can include higher
risks of toxicity, allergenicity, antibiotic
resistance, immune-suppression and
cancer. As for environmental impacts, the
use of genetic engineering in agriculture
could lead to uncontrolled biological
pollution, threatening numerous microbial,
plant and animal species with extinction,
and the potential contamination of nongenetically engineered life forms with
novel and possibly hazardous genetic
material."
(http://www.centerforfoodsafety.org/gene
ticall7.cfm)
SOther possible problems:
SUnintended harm to other
organisms
SReduced effectiveness of pesticides
SGene transfer to non-target species
SAllergies
SUnknown effects
Genetic Engineer Foods
Case Study
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Pusztai potato data
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Pusztai reportedly fed rats potatoes genetically modified to have snowdrop lectin (which is
an insecticide). the rats had stunted growth + immune system damage
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Controversy: confusion over the lectin was from snowdrop (cool) or jackbean (poisonous)
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research republished in october 1999, reviewed by 6 reviewers. “the paper did not mention
stunted growth or immunity issues, but reported that rats fed on potatoes genetically
modified with the snowdrop lectin had "thickening in the mucosal lining of their colon and
their jejunum" when compared with rats fed on non modified potatoes“
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While the implications of this study are alarming, the study had a number of holes and its
results cannot be taken to reflect for Genetic Engineering.
Genetic Engineered Foods
Official Word on Safety
S GM foods are highly regulated and they must pass extensive safety
testing before reaching market.
S GM foods have been consumed by hundreds of millions of people so far
with no reported health problems to date.
S Still it is possible that genetic engineering can unintentionally transfer
allergens between foods. Also Genetic Engineering can create new
allergens.
S Genetic Engineering has only been around for 15 years. There are
worries that long-term problems involving GM foods could be in our
future.
Medical uses of Genetic
Engineering
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Pigs are often chosen as transgenic animals because their physiology and organ size
are so similar to humans. The hope is that pig organs can be used for organ
transplantation, known as xenotransplantation.
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This will alleviating the shortage of human hearts and kidneys, which are in scarce supply.
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Researchers are also exploring the use of cell transplantation therapy for patients with
spinal cord injury or Parkinson’s disease. There are several drawbacks to
xenotransplantation.
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Additionally, commercial companies seek to derive therapeutic proteins, such as
monoclonal antibodies, from the milk of transgenic cows, goats, rabbits, and mice and
use them to administer drugs in treatment of rheumatoid arthritis, cancer, and other
autoimmune disorders.9
Medical uses of Genetic
Engineering 2
S Other uses of this transgenic combination include
growing tissue on a scaffolding, or supporting framework.
This then can be used as a temporary skin substitute for
healing wounds or burns or as replacement cartilage,
heart valves, cerebrospinal shunts, or even collagen
tubes to guide re-growth of nerves that have been
injured.
Medical uses of Genetic
Engineering 3
S Scientists harvest stem cells that can be used to
study human development and to treat disease.
Stem cells are important to biomedical
researchers because they can be used to
generate virtually any type of specialized cell in
the human body. The extraction process destroys
the embryo, which raises a variety of ethical
concerns.
S Ex= Stem cells since they are so versatile they can be
created into cardiac tissue, spinal tissue and maybe
even nerve tissue. Stem cells may be the key to curing
diseases caused by the erosions of nerves such as
Alzheimers and ALS.
Ethical problems
S If the blending of nonhuman animal and human DNA results,
intentionally or not, in trans-species entities possessing
degrees of intelligence or sentience never before seen in
nonhuman animals, should these entities be given rights and
special protections?
S It is possible that in blending DNA of different species we
might be making our subjects susceptible to new forms of
disease.
S Could we inadvertently create a super-disease?
S Is it right for parents to genetically alter their children before
birth?
What is Synthetic Biology
S Foundational Ideas
S Automated DNA Construction
S Standards of Abstraction
S Goals
S Organization of genetic information
S Registry of Standard Parts
S Built up through iGEM
S Open-source biological programming language
S Scalable engineering framework
Abstraction
Banana Biobrick
Transcription terminator for the E.coli
RNA polymerase
Promoter Ribosome
binding site
(lacI
regulated)
T1 from E. coli rrnB
alcohol acetyltransferase I;
converts isoamyl alcohol to
isoamyl acetate (banana odor)
Past projects
S Synthetic blood
S Banana E. coli
S Arsenic biosensor
S HIV “Virotrap”
S Self-organized pattern
formation