All that we are is the result of what we have thought
Buddha
For what shall it profit a man, if he shall gain
the whole world and lose his own soul?
The Bible
Introduction
While plant biotechnology has been used for centuries to enhance plants,
microorganisms and animals for food, only recently has it allowed for
the transfer of genes from one organism to another. Yet there is now a
widespread controversy over the harmful and beneficial effects of
genetic engineering to which, at this time, there seems to be no
concrete solution. The ideas below are expected to bring in a bit of
clearance into the topic. Here I’m going to reveal some facts concerning
genetic engineering, specially the technology, its weak and strong
points (if any). Probably the information brought is a bit too
prejudiced, for I’m certainly not in favor of making jokes with nature,
but I really tried to find some good things about GE.
What is genetic engineering?
Genetic engineering is a laboratory technique used by scientists to
change the DNA of living organisms.
DNA is the blueprint for the individuality of an organism. The organism
relies upon the information stored in its DNA for the management of
every biochemical process. The life, growth and unique features of the
organism depend on its DNA. The segments of DNA which have been
associated with specific features or functions of an organism are called
genes.
Molecular biologists have discovered many enzymes which change the
structure of DNA in living organisms. Some of these enzymes can cut and
join strands of DNA. Using such enzymes, scientists learned to cut
specific genes from DNA and to build customized DNA using these genes.
They also learned about vectors, strands of DNA such as viruses, which
can infect a cell and insert themselves into its DNA.
With this knowledge, scientists started to build vectors which
incorporated genes of their choosing and used the new vectors to insert
these genes into the DNA of living organisms. Genetic engineers believe
they can improve the foods we eat by doing this. For example, tomatoes
are sensitive to frost. This shortens their growing season. Fish, on the
other hand, survive in very cold water. Scientists identified a
particular gene which enables a flounder to resist cold and used the
technology of genetic engineering to insert this ‘anti-freeze’ gene into
a tomato. This makes it possible to extend the growing season of the
tomato.
At first glance, this might look exciting to some people. Deeper
consideration reveals serious dangers.
Techniques
There are 4 types of genetic engineering which consist of recombinant
engineering, microinjection, electro and chemical poration, and also
bioballistics.
r-DNA technology
The first of the 4, recombinant engineering, is also known as r-DNA
technology. This technology relies on biological vectors such as
plasmids and viruses to carry foreign genes into cells. The plasmids are
small circular pieces of genetic material found in bacteria that can
cross species boundaries. These circular pieces can be broken, which
results with an addition of a new genetic material to the broken
plasmids. The plasmids, now joined with the new genetic material, can
move across microbial cell boundaries and place the new genetic material
next to the bacterium’s own genes. After this takes place, the bacteria
will then take up the gene and will begin to produce the protein for
which the gene codes. In this technique, the viruses also act as
vectors. They are infectious particles that contain genetic material to
which a new gene can be added. Viruses carry the new gene into a
recipient cell driving the process of infecting that cell. However, the
viruses can be disabled so that when it carries a new gene into a cell,
it cannot make the cell reproduce or make copies of the virus.
Microinjection
The next type of genetic engineering is referred to as microinjection.
This technique does not rely on biological vectors, as does r-DNA. It is
somewhat of a simple process. It is the injecting of genetic material
containing the new gene into the recipient cell. Where the cell is large
enough, injection can be done with a fine-tipped glass needle. The
injected genes find the host cell genes and incorporate themselves among
them.
Electro and chemical poration
This technique is a direct gene transfer involving creating pores or
holes in the cell membrane to allow entry of the new genes. If it is
done by bathing cells in solutions of special chemicals, then it is
referred to as chemical poration. However, if it goes through subjecting
cells to a weak electric current, it is called electroporation.
Bio ballistics
This last technique is a projectile method using metal slivers to
deliver the genetic material to the interior of the cell. These small
slivers, which must be smaller than the diameter of the target cell, are
coated with genetic material. The coated slivers are propelled into the
cells using a shotgun. After this has been done, a perforated metal
plate stops the shell cartridge but still allows the slivers to pass
through and into living cells on the other side. Once inside, the
genetic material is transported to the nucleus where it is incorporated
among host cells.
The history of GE
The concept was first introduced by an Australian monk named Gregor
Mendel in the 19th century. His many experiments cemented a foundation
for future scientists and for the founding concepts in the study of
genetics.
Throughout Mendel’s life, he was a victim of criticism and ridicule by
his fellow monks for his “foolish” experiments. It took 35 years until
he was recognized for his experiments and known for the selective
breeding process. Mendel’s discoveries made scientists wonder how
information was transferred from parent to offspring and whether the
information could be captured and/or manipulated.
James D. Watson and Francis H. C. Crick were curious scientists who
later became known as the founding fathers of genetic engineering.
Watson and Crick wanted to determine how genetic blueprints are
determined and they also proposed that DNA structures are genetic
messengers or that chemical compounds of proteins and amino acids all
come together as a way to rule out characteristics and traits. These 2
scientists produced a code of DNA and thus answered the question of how
characteristics are determined. They also established that DNA are the
building blocks of all organisms.
Selective breeding and genetic engineering
Selective breeding and genetic engineering are “both used for the
improvement of human society.” However, selective breeding is a much
longer and more expensive process than genetic engineering. It takes
genetic engineering only one generation of offspring to see and study
improvement as opposed to selective breeding where many generations are
necessary. Therefore, it costs more to observe many generations.
Selective breeding is known as the natural way to engineer genes while
genetic engineering is more advanced, technical, scientific, complex and
is inevitable in out future.
What are the dangers?
Many previous technologies have proved to have adverse effects
unexpected by their developers. DDT, for example, turned out to
accumulate in fish and thin the shells of fish-eating birds like eagles
and ospreys. And chlorofluorocarbons turned out to float into the upper
atmosphere and destroy ozone, a chemical that shields the earth from
dangerous radiation. What harmful effects might turn out to be
associated with the use or release of genetically engineered organisms?
This is not an easy question. Being able to answer it depends on
understanding complex biological and ecological systems. So far,
scientists know of no generic harms associated with genetically
engineered organisms. For example, it is not true that all genetically
engineered foods are toxic or that all released engineered organisms are
likely to proliferate in the environment. But specific engineered
organisms may be harmful by virtue of the novel gene combinations they
possess. This means that the risks of genetically engineered organisms
must be assessed case by case and that these risks can differ greatly
from one gene-organism combination to another.
So far, scientists have identified a number of ways in which genetically
engineered organisms could potentially adversely impact both human
health and the environment. Once the potential harms are identified, the
question becomes how likely are they to occur. The answer to this
question falls into the arena of risk assessment.
In addition to posing risks of harm that we can envision and attempt to
assess, genetic engineering may also pose risks that we simply do not
know enough to identify. The recognition of this possibility does not by
itself justify stopping the technology, but does put a substantial
burden on those who wish to go forward to demonstrate benefits.
Fundamental Weaknesses of the Concept
Imprecise Technology—A genetic engineer moves genes from one organism to
another. A gene can be cut precisely from the DNA of an organism, but
the insertion into the DNA of the target organism is basically random.
As a consequence, there is a risk that it may disrupt the functioning of
other genes essential to the life of that organism. (Bergelson 1998)
Side Effects—Genetic engineering is like performing heart surgery with a
shovel. Scientists do not yet understand living systems completely
enough to perform DNA surgery without creating mutations which could be
harmful to the environment and our health. They are experimenting with
very delicate, yet powerful forces of nature, without full knowledge of
the repercussions. (Washington Times 1997)
Widespread Crop Failure—Genetic engineers intend to profit by patenting
genetically engineered seeds. This means that, when a farmer plants
genetically engineered seeds, all the seeds have identical genetic
structure. As a result, if a fungus, a virus, or a pest develops which
can attack this particular crop, there could be widespread crop failure.
(Robinson 1996)
Threatens Our Entire Food Supply—Insects, birds, and wind can carry
genetically altered seeds into neighboring fields and beyond. Pollen
from transgenic plants can cross-pollinate with genetically natural
crops and wild relatives. All crops, organic and non-organic, are
vulnerable to contamination from cross-pollinatation. (Emberlin 1999)
Health Hazards
Here are the some examples of the potential adverse effects of
genetically engineered organisms may have on human health. Most of these
examples are associated with the growth and consumption of genetically
engineered crops. Different risks would be associated with genetically
engineered animals and, like the risks associated with plants, would
depend largely on the new traits introduced into the organism.
New Allergens in the Food Supply
Transgenic crops could bring new allergens into foods that sensitive
individuals would not know to avoid. An example is transferring the gene
for one of the many allergenic proteins found in milk into vegetables
like carrots. Mothers who know to avoid giving their sensitive children
milk would not know to avoid giving them transgenic carrots containing
milk proteins. The problem is unique to genetic engineering because it
alone can transfer proteins across species boundaries into completely
unrelated organisms.
Genetic engineering routinely moves proteins into the food supply from
organisms that have never been consumed as foods. Some of those proteins
could be food allergens, since virtually all known food allergens are
proteins. Recent research substantiates concerns about genetic
engineering rendering previously safe foods allergenic. A study by
scientists at the University of Nebraska shows that soybeans genetically
engineered to contain Brazil-nut proteins cause reactions in individuals
allergic to Brazil nuts.
Scientists have limited ability to predict whether a particular protein
will be a food allergen, if consumed by humans. The only sure way to
determine whether protein will be an allergen is through experience.
Thus importing proteins, particularly from nonfood sources, is a gamble
with respect to their allergenicity.
Antibiotic Resistance
Genetic engineering often uses genes for antibiotic resistance as
“selectable markers.” Early in the engineering process, these markers
help select cells that have taken up foreign genes. Although they have
no further use, the genes continue to be expressed in plant tissues.
Most genetically engineered plant foods carry fully functioning
antibiotic-resistance genes.
The presence of antibiotic-resistance genes in foods could have two
harmful effects. First, eating these foods could reduce the
effectiveness of antibiotics to fight disease when these antibiotics are
taken with meals. Antibiotic-resistance genes produce enzymes that can
degrade antibiotics. If a tomato with an antibiotic-resistance gene is
eaten at the same time as an antibiotic, it could destroy the antibiotic
in the stomach.
Second, the resistance genes could be transferred to human or animal
pathogens, making them impervious to antibiotics. If transfer were to
occur, it could aggravate the already serious health problem of
antibiotic-resistant disease organisms. Although unmediated transfers of
genetic material from plants to bacteria are highly unlikely, any
possibility that they may occur requires careful scrutiny in light of
the seriousness of antibiotic resistance.
In addition, the widespread presence of antibiotic-resistance genes in
engineered food suggests that as the number of genetically engineered
products grows, the effects of antibiotic resistance should be analyzed
cumulatively across the food supply.
Production of New Toxins
Many organisms have the ability to produce toxic substances. For plants,
such substances help to defend stationary organisms from the many
predators in their environment. In some cases, plants contain inactive
pathways leading to toxic substances. Addition of new genetic material
through genetic engineering could reactivate these inactive pathways or
otherwise increase the levels of toxic substances within the plants.
This could happen, for example, if the on/off signals associated with
the introduced gene were located on the genome in places where they
could turn on the previously inactive genes.
Concentration of Toxic Metals
Some of the new genes being added to crops can remove heavy metals like
mercury from the soil and concentrate them in the plant tissue. The
purpose of creating such crops is to make possible the use of municipal
sludge as fertilizer. Sludge contains useful plant nutrients, but often
cannot be used as fertilizer because it is contaminated with toxic heavy
metals. The idea is to engineer plants to remove and sequester those
metals in inedible parts of plants. In a tomato, for example, the metals
would be sequestered in the roots; in potatoes in the leaves. Turning on
the genes in only some parts of the plants requires the use of genetic
on/off switches that turn on only in specific tissues, like leaves.
Such products pose risks of contaminating foods with high levels of
toxic metals if the on/off switches are not completely turned off in
edible tissues. There are also environmental risks associated with the
handling and disposal of the metal-contaminated parts of plants after
harvesting.
Enhancement of the Environment for Toxic Fungi
Although for the most part health risks are the result of the genetic
material newly added to organisms, it is also possible for the removal
of genes and gene products to cause problems. For example, genetic
engineering might be used to produce decaffeinated coffee beans by
deleting or turning off genes associated with caffeine production. But
caffeine helps protect coffee beans against fungi. Beans that are unable
to produce caffeine might be coated with fungi, which can produce
toxins. Fungal toxins, such as aflatoxin, are potent human toxins that
can remain active through processes of food preparation.
No Long-Term Safety Testing
Genetic engineering uses material from organisms that have never been
part of the human food supply to change the fundamental nature of the
food we eat. Without long-term testing no one knows if these foods are
safe.
Decreased Nutritional Value
Transgenic foods may mislead consumers with counterfeit freshness. A
luscious-looking, bright red genetically engineered tomato could be
several weeks old and of little nutritional worth.
Problems Cannot Be Traced
Without labels, our public health agencies are powerless to trace
problems of any kind back to their source. The potential for tragedy is
staggering.
Side Effects can Kill
37 people died, 1500 were partially paralyzed, and 5000 more were
temporarily disabled by a syndrome that was finally linked to tryptophan
made by genetically-engineered bacteria.
Unknown Harms
As with any new technology, the full set of risks associated with
genetic engineering have almost certainly not been identified. The
ability to imagine what might go wrong with a technology is limited by
the currently incomplete understanding of physiology, genetics, and
nutrition.
Potential Environmental Harms
Increased Weediness
One way of thinking generally about the environmental harm that
genetically engineered plants might do is to consider that they might
become weeds. Here, weeds means all plants in places where humans do not
want them. The term covers everything from Johnson grass choking crops
in fields to kudzu blanketing trees to melaleuca trees invading the
Everglades. In each case, the plants are growing unaided by humans in
places where they are having unwanted effects. In agriculture, weeds can
severely inhibit crop yield. In unmanaged environments, like the
Everglades, invading trees can displace natural flora and upset whole
ecosystems.
Some weeds result from the accidental introduction of alien plants, but
many were the result of purposeful introductions for agricultural and
horticultural purposes. Some of the plants intentionally introduced into
the United States that have become serious weeds are Johnson grass,
multiflora rose, and kudzu. A new combination of traits produced as a
result of genetic engineering might enable crops to thrive unaided in
the environment in circumstances where they would then be considered new
or worse weeds. One example would be a rice plant engineered to be
salt-tolerant that escaped cultivation and invaded nearby marine
estuaries.
Gene Transfer to Wild or Weedy Relatives
Novel genes placed in crops will not necessarily stay in agricultural
fields. If relatives of the altered crops are growing near the field,
the new gene can easily move via pollen into those plants. The new
traits might confer on wild or weedy relatives of crop plants the
ability to thrive in unwanted places, making them weeds as defined
above. For example, a gene changing the oil composition of a crop might
move into nearby weedy relatives in which the new oil composition would
enable the seeds to survive the winter. Overwintering might allow the
plant to become a weed or might intensify weedy properties it already
possesses.
Change in Herbicide Use Patterns
Crops genetically engineered to be resistant to chemical herbicides are
tightly linked to the use of particular chemical pesticides. Adoption of
these crops could therefore lead to changes in the mix of chemical
herbicides used across the country. To the extent that chemical
herbicides differ in their environmental toxicity, these changing
patterns could result in greater levels of environmental harm overall.
In addition, widespread use of herbicide-tolerant crops could lead to
the rapid evolution of resistance to herbicides in weeds, either as a
result of increased exposure to the herbicide or as a result of the
transfer of the herbicide trait to weedy relatives of crops. Again,
since herbicides differ in their environmental harm, loss of some
herbicides may be detrimental to the environment overall.
Squandering of Valuable Pest Susceptibility Genes
Many insects contain genes that render them susceptible to pesticides.
Often these susceptibility genes predominate in natural populations of
insects. These genes are a valuable natural resource because they allow
pesticides to remain as effective pest-control tools. The more benign
the pesticide, the more valuable the genes that make pests susceptible
to it.
Certain genetically engineered crops threaten the continued
susceptibility of pests to one of nature’s most valuable pesticides: the
Bacillus thuringiensis or Bt toxin. These “Bt crops” are genetically
engineered to contain a gene for the Bt toxin. Because the crops produce
the toxin in most plant tissues throughout the life cycle of the plant,
pests are constantly exposed to it. This continuous exposure selects for
the rare resistance genes in the pest population and in time will render
the Bt pesticide useless, unless specific measures are instituted to
avoid the development of such resistance.
Poisoned Wildlife
Addition of foreign genes to plants could also have serious consequences
for wildlife in a number of circumstances. For example, engineering crop
plants, such as tobacco or rice, to produce plastics or pharmaceuticals
could endanger mice or deer who consume crop debris left in the fields
after harvesting. Fish that have been engineered to contain
metal-sequestering proteins (such fish have been suggested as living
pollution clean-up devices) could be harmful if consumed by other fish
or raccoons.
Creation of New or Worse Viruses
One of the most common applications of genetic engineering is the
production of virus-tolerant crops. Such crops are produced by
engineering components of viruses into the plant genomes. For reasons
not well understood, plants producing viral components on their own are
resistant to subsequent infection by those viruses. Such plants,
however, pose other risks of creating new or worse viruses through two
mechanisms: recombination and transcapsidation.
Recombination can occur between the plant-produced viral genes and
closely related genes of incoming viruses. Such recombination may
produce viruses that can infect a wider range of hosts or that may be
more virulent than the parent viruses.
Transcapsidation involves the encapsulation of the genetic material of
one virus by the plant-produced viral proteins. Such hybrid viruses
could transfer viral genetic material to a new host plant that it could
not otherwise infect. Except in rare circumstances, this would be a
one-time-only effect, because the viral genetic material carries no
genes for the foreign proteins within which it was encapsulated and
would not be able to produce a second generation of hybrid viruses.
Gene Pollution Cannot Be Cleaned Up
Once genetically engineered organisms, bacteria and viruses are released
into the environment it is impossible to contain or recall them.
Unlike chemical or nuclear contamination, negative effects are
irreversible.
DNA is actually not well understood.
Yet the biotech companies have already planted millions of acres with
genetically engineered crops, and they intend to engineer every crop in
the world.
The concerns above arise from an appreciation of the fundamental role
DNA plays in life, the gaps in our understanding of it, and the vast
scale of application of the little we do know. Even the scientists in
the Food and Drug administration have expressed concerns.
Unknown Harms
As with human health risks, it is unlikely that all potential harms to
the environment have been identified. Each of the potential harms above
is an answer to the question, “Well, what might go wrong?” The answer to
that question depends on how well scientists understand the organism and
the environment into which it is released. At this point, biology and
ecology are too poorly understood to be certain that question has been
answered comprehensively.
Any pros?
Certainly, there should be some. Still, most of them are connected with
commercial gains for genetic engineering companies. A popular claim,
that farmers will benefit, is simply not true. It is just the same thing
with consumers. No one is going to feed the poorest with GE products for
the famine in many underdeveloped countries is simply the matter of
inability to buy food, not lack of it. So today, at the present stage of
development, we hardly need GE expanding on food products, needless to
say about animal and human cloning. Incidentally, some daydreaming
proponents of GE really believe that mankind will not be able to survive
without it. According to them, we will certainly have to genetically
upgrade ourselves in response to governmental activities. The humans
will be able to hibernate – just like some animals – to cover long
distances without aging, and, probably, will become immortal…
Still, what about the present need of GE? Where can GE particularly be
used now without a threat to the humans and the environment?
So, scientists say that genetic engineering can make it possible to
battle disease (cancer, in particular), disfigurement, and other
maladies through a series of medical breakthroughs that will be
beneficial to the human race. Moreover, cloning will be able to end the
extinction of many endangered species. The main question is whether we
can trust genetic engineering. The fact is that even genetically changed
corn is already killing species.
The recent research showed that pollen from genetically engineered corn
plants is toxic to monarch butterflies. Corn plants produce huge
quantities of pollen, which dusts the leaves of plants growing near corn
fields. Close to half the monarch caterpillars that fed on milkweed
leaves dusted with Bt corn pollen died. Surviving caterpillars were
about half the size of caterpillars that fed on leaves dusted with
pollen from non-engineered corn. Something is wrong with the engineered
products – they are different, so we cannot be sure about the effect
they will bring about.
So, is the technology trustworthy? I suppose not.
Conclusion
So, do we need it? There are far too many disadvantages of GE and far
too many unpredictable things may happen. The humans are amateurs in
this area, in fact, they are just like a monkey taught to press PC
buttons. We have almost no experience, the technology has not yet
evolved enough. I believe, we should wait, otherwise we may give birth
to a trouble, which would be impossible to resolve.
References
David Heaf ‘Pros and Cons of Genetic Engineering’, 2000, ifgene;
Ricarda Steinbrecher, ‘From Green to Gene Revolution’, The
Ecologist,
Vol 26 No 6;
‘Genetic Engineering Kills Monarch Butterflies’, Nature Magazine, May
19,1999;
‘Who’s Afraid of Genetic Engineering?’ The New York Times August 26,
1998;
Sara Chamberlain ‘Techno-foods’, August 19, 1999, The New
Internationalist;
W French Anderson, ‘Gene Therapy’ in Scientific American, September
1995;
Nature Biotechnology Vol 14 May 1996;
Andrew Kimbrell ‘Breaking the Law of Life’ in Resurgence May/June 1997
Issue 182;
Jim Hightower ‘What’s for dinner?’, May 29, 2000.
Contents TOC \o “1-2”
Introduction PAGEREF _Toc501543429 \h 1
What is genetic engineering? PAGEREF _Toc501543430 \h 1
Techniques PAGEREF _Toc501543431 \h 1
The history of GE PAGEREF _Toc501543432 \h 2
Selective breeding and genetic engineering PAGEREF _Toc501543433 \h 3
What are the dangers? PAGEREF _Toc501543434 \h 3
Fundamental Weaknesses of the Concept PAGEREF _Toc501543435 \h 3
Health Hazards PAGEREF _Toc501543436 \h 4
Potential Environmental Harms PAGEREF _Toc501543437 \h 6
Any pros? PAGEREF _Toc501543438 \h 8
Conclusion PAGEREF _Toc501543439 \h 9
References PAGEREF _Toc501543440 \h 10
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