Throughout
history, humans have selected particular plants for cultivation as crops
because they may be edible, produce good fibers, contain useful chemicals or
have a high rate of photosynthesis. A plant that has a high rate of
photosynthesis has a high rate of productivity. In this way crops have steadily
improved. This process is called artificial selection, which is to select
alleles for characteristics which are agriculturally valuable. Today scientists
are able to put new traits into a plant which was previously unavailable. For example, there are fishes that survive at very low
temperatures and these genes have been taken and have been transferred into the
plants to see if the plant is able to adapt to cold temperatures.
When an organism
is said to have received a new gene it is said to be transformed. Agrobacterium
Tumefaciens is a widely used bacterium for the insertion of the desired
genes into plants. Some of the qualities that scientists like to enhance in
plants are resilience, resistant to herbicides, a good harvestable quantity,
nourishing quality, and resistant to spoilage. By modifying a plants genetic
material in a way that does not occur naturally, it could lead to a number of
advantages and mankind could benefit greatly. For example, a plant with an
improved efficiency of the uptake of mineral salts will have a reduced
fertilizer input. A plant with improved ability to withstand drought or high
salt concentrations will be able to survive on land where soil or climate is
unsuitable. A plant which is resistant to disease is able to reduce pesticide
input and thus crop losses are reduced. A plant which is frost resistance the
growing and the harvest season can be extended. And also a plant which has a
control in ripening of fruits can be post harvested and losses can thus be
reduced.
The bacterium Bacillus thuringiensis produces a protein which
is toxic to a variety of insect larvae (John Adds. et. al. 2003).
The gene for the production of this protein is located in the plasmids of the
bacterium. The cells can be cultured to form a colony and insect resistant
plants can be produced, which posses a natural defence against insect pests. This technique has been
used to produce genetically modified plants such as corn plant known as BT corn.
The animals that
benefit humans mostly are cattle, goats, sheeps and pigs. Goats, cattles and
sheeps are excellent example of bioreactors. By inserting a gene of interest animals
can be transformed into bioreactors (living factories of important chemicals).
The reason why they act as a good bioreactor is due to the presence of large
mammary systems. Cows can produce large amounts of milk. But
human genes cannot be inserted into the cows or the goats to produce proteins.
Also the tissues and the organs from the cows or the goats cannot be used for
human transplant, it is due to the fact that they are very different from us, and
their organs are of different size and is located in a different place.
Unlike
the goats and the cows, the tissues and the organs of pigs are used in various
transplants in human. For instance, people who have damaged arteries and veins
in the legs and arms can be replaced with the arteries and veins from pigs.
Even pig heart valves, kidneys and the livers can be used for human transplant.
The reason why pig tissues and organs can be used for human transplant is that
the pig and the human protein are similar. Also they have the same physiological
systems and organ tissues as humans. One major advantage that human benefit
from this is that when the pig protein is isolated in order to insert into
humans, the immune systems attack towards the foreign particle is less.
Biotechnology
also has benefits in the diagnosis, treatment and prevention of genetic and non
genetic diseases. A lot of effort is
being done to understand the disease processes such as cancer, heart diseases
and so on. Since, almost the entire human genome has now been acquired; this
can be an important step of understanding genetic diseases in a much clearer
view. Antibodies which can be studied, tested and manipulated can be produced
in large amounts in cell cultures. White blood cells known as lymphocytes are
responsible for secretion of defensive proteins (antibodies) that bind to
microbes and mark them for elimination (Campbell & Reece, 2005). In general
antibodies are the key to body’s defence against diseases.
In developing
countries such as the third world countries, genetic engineering may offer some
solutions for disease prevention. In
these countries the main staple food may lack essential nutrients required by
the body, such as vitamins, minerals, proteins and other important compounds. Marasmus
and kwashiorkor are forms of protein- energy malnutrition which occur in
children in the developing world (John Adds. et. al. 2003). Rice is a
very important crop in the global scale and is also low in vitamin A (retinol).
Lack of this vitamin leads to blindness. Therefore, by genetically introducing
the genes for the production of vitamin A into rice this problem could be
solved. The genetically engineered rice is called the “golden
rice”. Many people in the developing countries do not have access or cannot
afford most of the important vaccines. In order to get people vaccinated, these
vaccines are inserted into the bananas. These bananas can now be fed to the
young. This method of vaccinating the people is one big advantage where people
benefit by obtaining the vaccine at an affordable level.
References
John
Adds, Erica Larkcom, Ruth Miller (2003). Respiration and coordination: revised
edition. Pg- 93
John
Adds, Erica Larkcom, Ruth Miller (2004). Genetics, evolution and biodiversity:
revised edition. Pg- 93
Neil
A. Campbell, Jane B. Reece (2005). Biology: seventh edition. Pearson
international edition Pg- 898. ISBN 0-321-26984-5
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