Outline:
Genetic engineering is a powerful and potentially very
dangerous tool. To alter the sequence of nucleotides of the DNA that
code for the structure of a complex living organism, can have extremely
ill effects although the potential benefits can be huge.
Before
advances in genetic applications, gene therapy was unheard of and
genetic defects were always inherited, plaguing generations. Today
genetic testing is widely available, such as prenatal karyotyping of
chromosomes to check for genetic abnormalities. Genetic testing is also
useful for families in which autosomal recessive disorders are known to
exist, when these are planning to have children. In addition, genetic
testing is available for people who might have inherited a genetic
disorder which only becomes apparent later in life (for example
Huntington's Disease). Individual choice decides whether a person would
rather know if they are particularly vulnerable to certain diseases or
more likely to die young. Knowing that your life may be short could
inspire you to make the most of it while it could equally well cause
severe depression.(genetic engineering)
Today`s advances in gene therapy make it
possible to even remove a faulty gene and replace it with a functioning
gene in cells lacking this function. Though these techniques are
available, they are still in the experimental stages. Somatic cell
therapy, for example, uses faulty genes to target the affected areas for
genetic treatment. This technique is beneficial in the treatment of
cancers and lung, blood and liver disorders. Since the treatment is
localised, any unwanted effects of this are not passed on to the next
generation.
A more controversial technique is the genetic
alteration of gametes which causes a permanent change for the organism
as well as for
subsequent generations. Of course if the gene is
corrected without further negative effects, the genetic disorder has
been
successfully eliminated; but if a problem arises it could pass on.
These
advances in genetic engineering make the possibility of "designer
babies" a reality. When the choice to change every aspect of every
characteristic of a child is available, who would refuse? Why have an
average child, when it is possible to have one with perfect health, good
looking, intelligent and matching every other desirable characteristic
which parents could want? The benefits seem endless: the potential for a
perfect society without physical imperfections, low intelligence nor
undesirable personality traits. How far this could go, is unpredictable;
theoretically humans could for example be made more efficient -
requiring less food but able to work harder.
However, one of the
problems with changing the structure of human DNA, is the subsequent
loss of natural variation. As well as the unattractive possibility of
very little variation in personalities and looks, the loss of natural
variation would stop the formation of new genes, thereby severely
decreasing the available gene pool. On the larger scale of life, natural
variation is vital for subtle adaptions that help species accommodate
to changing environments. If genetic alterations become widespread,
genes required for particular circumstances or different environments
that may be encountered by the organism, could conceivably be bred out.
If then the organism encounters a change without the gene which would
have made adaptation possible, it could suffer or even perish.
Another
large problem with all types of genetic engineering is the
interdependence of genes: while on the one hand one gene may code for
several features, on the other hand many genes are frequently required
to code for one characteristic. While chromosome mapping is useful,
without test crossing with every possible variable characteristic of an
organism, it cannot be known what the functions of each gene are. Hence
when a gene is removed, what is known about the function of that gene
may not be all it codes for. The removed gene may also have a part to
play in other functions. Similarly, the inserted gene may have other
functions that are not known about. Some of the effects of these unknown
gene functions may be noticed immediately and possibly be rectifiable,
while others without immediate effect may cause significant long term
changes. Little is known about the long term effects and potential
dangers which may be inherited before they are noticed. Such problems
may be cumulative and become harder to stop through time as the spread
of new genetic problems continues through generations.
This
problem of inadequate knowledge regarding a gene's complete function
applies also to the use of genetic engineering in food production. Be it
livestock or crops, the alteration of genes, for example to boost
growth, could have side effects such as weakening resistance to a
particular disease. The inserted gene could even code for something
harmful to humans. These problems may not even be immediately noticed
and are hard to stop once cattle have been bred, crops sown or
distributed.
On the other hand, the benefits to humans are
obvious where gene replacement has been successful in improving aspects
of food production. For example, production costs can be lowered and
health, taste and look of a product maximised. Equally, a lot of food
shortage problems in the Third World could be solved by adapting crops
to grow in such harsh conditions.
An extreme idea of the future of
meat production (Man Made Life- Jeremy Cherfas) involves the
engineering of entirely new forms of meat: "a vast organ culture of
immortal muscle cells supplied with a steady stream of crude nutrients
(perhaps from other engineered cells) and harvested by hacking off a
slab". Personally the idea of this is extremely unappealing but it is
clear that the efficiency of meat production would rocket as the result
of such an advance. In addition, the resources saved in such forms of
meat production could be used elsewhere for human benefit.
An
example of another controversial but popentially beneficial form of
genetic engineering is the alteration of pig DNA to suit human
immunology. Recently the problem of organ donor shortage has become
apparent due to increases in road safety and life saving technology. A
simple solution is to use pig organs which function in similar ways and
have a similar size to human organs. The immunology of pigs is also
similar to that of humans but there is still the problem of organ
rejection. Human antibodies would recognize the pig tissue as foreign
and either destroy it or cause harm to the recipient.
The solution
is to change the antigenic properties of the pig tissue by genetically
introducing human DNA that won't be rejected by the human immune system.
Hence a breed of pigs containing human elements in their DNA was
created. The obvious benefits would be a ready supply of organs not
dependant on the death of a
healthy person as well as advance
preparation time for the transplant to minimise the risk of rejection.
The main problem consists of the possible introduction of new diseases
to humans. A particular retrovirus has been discovered which, harmless
to pigs, has the potential to cause severe ill effects in humans.
All
the previously mentioned applications of genetic engineering have had
clear benefits to the human species in spite of equally apparent risks.
However, one of the perhaps most dangerous risks of the new advances is
their undeniable potential for biological warfare. This potential for
engineering deadlier and more resistant infections or diseases scares
all nations. Weapons could now be directed at the water supply or even
crops grown by the enemy. Strains of pathogens could be tailored to the
enemies strain of livestock or crops, starving a nation into surrender.
By changing other common diseases, an antidote could be found to
vaccinate allied populations while only the enemy would suffer. The
benefit to the inflicting power is removal of enemy population without
destroying buildings and resources (as an atomic weapon would). Since
all sides are likely to have some form of biological weapon, however,
none would go unaffected, thereby causing large scale suffering. This
problem would be worsened if fast spreading diseases were used - without
treatment whole populations could disappear in very little time.
I
feel that although some of the applications of actual genetic
'engineering' could be of immense use to humans (as the applications of
gentic testing already are), too little is known about genetic structure
to inflict the risks involved on the population. Despite this,
genetically altered food has already started to fill the supermarkets,
only labelled as such if genetically altered substance is present (and
not when genetic engineering has taken place in the production process).
"It
has been estimated that the entire human genome will be mapped and all
important genes sequenced before the end of the century" (British
Medical Journal Vol.299). Surely with advances at this rate, these
visions of the future of genetic engineering are not as far off as I
would like to think. The potential risks involved to humanity rank
alongside developments such as nuclear power in that the extent to which
the whole population of this planet could be affected, is immense.
Equally, the wide range of applications of genetic engineering make it
possibly of the greatest use since the discovery of electricity.
