are produced, which are called callus. The new transgene is then inserted into these cells using one of
the following techniques; agrobacterium, mircrofibres, electroporation and the ‘gene gun’. The main
goal of each of these techniques is to transport the new gene or genes into the nucleus of a callus cell
without killing it in the process. The transformed plant cells are then regenerated into transgenic plants
which are grown to maturity. The seed they produce is then collected and more plants are grown.
The fifth and final process is to continue breeding the transgenic plant with elite breeding using
traditional plant breeding methods to combine the desired traits of the elite and transgenic plant into a
single line. Then the offspring are repeatedly crossed back to the elite line to obtain a high yielding
transgenic line. The result will be a plant with a yield potential close to current hybrids that expresses
the trait encoded by the new transgene.
These five processes are basically universal for the genetic engineering of any plant. However, the
length of time required to complete all five processes varies depending upon the gene, crop species and
resources. It can typically take anywhere between six to 15 years for a new transgenic plant hybrid is
ready to be grown for production in fields.
Artificial selection could be described as a ‘crude’ form of genetic engineering, as in effect an aspect of
the organisms’ form or function is being altered or modified in some way, but through trial and error as
parents which have the desired characteristics are selected to breed in order to produce offspring which
are more useful for the specific task or tasks they have been bred for. Then in turn, the offspring are
bred again, and again until the desired characteristics are prominent and no more further breeding is
required.
Another term which is commonly associated with genetic engineering is cloning. The word cloning,
when associated with genetic engineering, has come to mean using genetic engineering techniques to
produce genetically identical organisms. Essentially, it means to make a copy of an organism. Cloning
is a vital part of the process of producing genetically modified organisms, as many copies of the altered
cells have to be made.
Whereas cloning a single cell is a relatively simple process, cloning can also be used to produce copies
of entire complex organisms. There have already been documented examples of sheep, monkeys and
mice being cloned, amongst other animals.
An important thing to realise about cloning however is that because the cloned (in this case animal)
organism is genetically identical, it does not in any way mean it will behave the same way and have the
same personality as the organism it was cloned from. This is because the upbringing of offspring is due
to the animals environment and not its genes. A clone of a human would look the same (unless
environmental influences had taken place, such as disfiguring scars) but would almost certainly be a
completely different person in the sense that he/she would have a different personality, as he/she
undoubtedly had different parents, lived somewhere else and had generally different experiences.
When genetic engineering or cloning is mentioned, all sorts of issues arise which in some cases sound
beneficial and in others quite worrying. Here such allegations and ideas are examined.
Possible benefits and arguments for artificial selection, genetic engineering and cloning are as
follows:
Artificial selection is hugely beneficial in enhancing the usefulness of organisms to mankind. It is a
technique which has been used for centuries and has changed little (apart from in scale). In has mainly
influenced food production and other products such as wool or cotton production, and in fact many of
the typical ‘farmyard’ animals are even plants are the result of extensive artificial selection.
Increased food yield is one possible benefit which could be acquired from genetic engineering. In fact
for years plants and animals have been subject to artificial selection to combine their most useful
elements, such as obesity, to increase food yield; amongst other resources, such as wool. Genetic
engineering could enhance this process, allowing it to be more effective and efficient, and therefore
could be part of the solution to the world’s ever increasing hunger.
Another possible benefit of genetic engineering could be the possibility of enhancing ourselves in
several ways. These could include genetically engineered babies which are not subject to inherited
diseases such as downs syndrome, or even as mundane as colour blindness and such like.
Infectious diseases could also be counter measured with gene implants that contain the proteins
necessary to combat disease, such as viral infection.
The growth of replacement limbs and organs is also a possible use of genetic engineering and cloning.
Genetic Engineering could also increase genetic diversity, and produce more variant alleles which could
then allow the opportunity to be crossed over and implanted into other species. For example, the drug
insulin is a vital part of the medication that diabetic people need, and with genetics engineering it is
possible to alter the genetics of wheat plants to grow insulin.
Possible disadvantages and arguments against genetic engineering are as follows:
As artificial selection is a technique which is centuries old, there is not real protest against it (at least
not that I can find). However, there is one main disadvantage to artificial selection, and that is that many
other less useful species of animals and plants have been ignored over time. This means that the useful
animal/plant hybrids have been bred extensively because of their usefulness, whilst at the same time
causing the populations of other animals and plants to decrease due to lack of demand and competition.
This has resulted in less genetic diversity, as more and more types of specific animals and plants have
increased in volume, and other species have become rare or extinct.
One of the main issues against genetic engineering and cloning is that of the ethical, social and religious
questions which are raised by such processes. Genetically engineering a babies genes so that it does not
fall victim to a hereditary disease might improve its quality of life - but then again is it right only to
offer this advantage to parents that can afford it? Such an issue is inevitable as genetic engineering will
undoubtedly be exploited for profit if such processes come about. However, genetically modifying a
babies genetic makeup so that it’s level of intelligence can be chosen, for example, raises many
arguments. Whose right is it to decide how your child will be? There is a danger that a ‘designer baby’
culture could arise if these alterations are allowed.
Many people also believe that such processes as cloning and genetic engineering are against ‘gods will’
and that as human beings we have no right to interfere with nature. While this is more a argument of
religion or faith, it could carry some sense. There are many reports on the Internet that suggest genetic
engineering as it stands is a rather crude process, in that the insertion of a new gene can not be guided
to a predetermined position in the genetic structure of the receiving organism, and much trial and error
is still involved.
The other main issue is that there may also be unknown and unforeseeable consequences of genetic
engineering. As well as the already mentioned commercialism, other problems could arise such as the
decrease in genetic diversity in nature, as mentioned with artificial selection.
Nature is an extremely complex inter-related chain consisting of many species linked in the food chain.
Some scientists believe that introducing genetically modified genes may have an irreversible effect with
consequences yet unknown. For example, if a hybrid crop is engineered so that it is resistant to natural
threats such as insects and it grows in poor conditions very easily, that would be very useful as
production of the crop would increase whilst money spent on pesticides and fertilisers could be put to
other uses. However, if the crop started to spread and began growing in un-agricultural areas, it could
start to get out of control and become a pest, or even start to dominate gene pools.
Conclusion.
I think that genetic engineering in general is beneficial and should provide us with plenty of new
opportunities which should most importantly increase standards of living.
However, I think it is very important that we as a whole, do not get caught up in the rush to use
genetically engineered organisms. It is a new form of science which should not be jumped into too
hastily, and more research and development should take place than is currently being done. This is
because there could be two possible consequences of not doing so.
First, as described earlier, we do not fully know or understand the whole process, and a gap in our
knowledge could have minor, if not major consequences upon the environment which could possibly be
irreversible.
Second,
public opinion is very much against genetic engineering even though many people do not understand it.
If genetic engineering is to succeed, then the general public need to be given more information on it’s
benefits, not just it’s potential disadvantages.
Genetic engineering borderlines on many moral issues, particularly involving religion, which questions
whether man has the right to manipulate the laws and course of nature.
So there obviously needs to be a fine balance between what is considered ‘right’ and what is considered
‘wrong’. If genetic engineering ever does
Also, there would need to be a fine balance between what is ‘right’, i.e., what is morally and socially
acceptable, and what is ‘wrong’. Once again, making sure a new-born child does not have a life-
threatening disorder must be a good thing, but making sure a child is intelligent or strong raises
question marks.
List of reference:
Biology for AQA
http://www.biology-online.org/2/13_genetic_engineering.htm
http://www.encarta.com
http://www.infoplease.com
http://www.ecoglobe.org.nz/gebiotec/gebiotec.htm
Giles Prowse 03/08/2003
Artificial selection and genetic engineering are two ways in which humans are able to manipulate
the form or function of living organisms (including themselves).
