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About
I am studying for a M.Sc. Science Communication at Imperial College London.
One of my courses was to design a science communication website. I have a blog
<link 1> describing the construction process for this website.
Since I have a degree in Biological Sciences with honours Plant Science from the
University of Edinburgh, genetic modification (GM) in plants seemed the logical
topic choice. It is part of the reason I became interested in science
communication. It is a controversial topic, which is yet again in the mainstream
media. I wanted to design a website that reflected my thoughts on GM. I am not
trying to present a definitive opinion on GM, simply reflect what I have been
taught during my degree. I would also like to add an international dimension
since I have lived in both the UK and USA.
This site is entirely my own opinion based on what I have been taught.
LINKS
[1] http://penblogsandbuildsawebsite.wordpress.com/
What is GM?
All organisms have genes, made up of DNA. Genetic modification (GM) describes
the process by which an organisms’ genetic material has been altered. On this
site, I will focus on what that means within the plant kingdom. GM can be
achieved through the insertion of genes. These genes can be from plants within
the same species, or from different species. The ultimate goal is to have a plant
with desirable traits. There are several techniques for GM, or plant
transformation. Descriptions can be found on the “How are GM plants made?”
<link> page.
§When it was first used / discovered
The first GM plant was created in 1983 [1]. It was a transgenic <definition>
tobacco plant [1]. This was made possible after Watson, Crick, Franklin and
James discovered that DNA was the smallest unit of life. Scientists began working
with bacteria [2]. Several decades of research lead up to the first plant
transformation [2]. As with any scientific discovery, it came after
[1]
http://news.bbc.co.uk/1/hi/special_report/1999/02/99/food_under_the_micro
scope/280868.stm
[2] http://www.whoinventedit.net/who-invented-genetic-engineering.html
§How it is different to cloning
Cloning produces an identical copy to the original. This is different to GM which
produces a plant with new genetic material. The techniques used are also
different; cloning uses an adult cell which is placed in an ovum with the nucleus
removed (definition). A small electrical charge is passed through which starts the
cell cycle.
Here is a video that explains GM at a GCSE level:
https://www.dropbox.com/home
How are GM plants made?
There are two main techniques for plant transformation:
Biogun <link>
Agrobacterium tumefaciens <link>
I will explain these techniques in slightly more detail, but I will focus on A.
tumefaciens. This is because it is the more efficient and elegant technique. It also
has an interesting story rooted in plant pathology.
§Bio gun
The biogun is pretty much how it sounds. A solution containing genetic material
(definition) is ‘shot’ at plant cells. The force of the action opens microscopic
holes where the DNA can enter.
§Agrobacterium tumefaciens
This bacterium, in the wild, causes a plant disease called crown gall (definition).
The clever bacterial mechanism is exploited for plant transformation. For more
information, please follow the link to the A. tumefaciens page <link>.
For both processes, this is by no means a definite event; most of the DNA will not
enter the cell. Even if it does, only a fraction will be taken up into the plant
genome (definition). Of those cells which take up the new DNA, only a small
number will be viable. The DNA may enter at a point that disrupts a vital plant
process or in an exon (definition) sequence.
A. tumefaciens
Agrobacterium tumefaciens causes Crown Gall disease. The bacterium has a very
clever mechanism for entering the plant cell. Like all bacteria, A. tumefaciens has
its DNA free within the cell. It also has an extra piece of DNA called a plasmid
(definition). For A. tumefaciens, this plasmid is called a tumour inducing (Ti)
plasmid because of the gall it causes when it infects a plant. The Ti plasmid has
several important elements. One is its ability to enter a plant cell and the other is
to insert its DNA into the plants genome (definition). Since this is precisely what
plant scientists need for GM, they remove the disease elements of the plasmid
and attach desirable traits for insertion into the plant genome. This video <link>
explains this at a GCSE level.
Where are GM plants used?
The legal status of GM food varies around the world. GM crops, according to
DEFRA (definition), are being grown in 29 countries worldwide <link 1>. There
are two GM crops that are allowed to be grown in the EU <link 1>. This is only
done in 6 countries, which does not include the UK. Although GM products can be
sold here, but only after being given permission by DEFRA <link 1>. In keeping
with EU legislation, all GM derived food must be clearly labelled.
In the USA, GM food is grown and on sale. This is because the FDA states that
bioengineered (definition) foods pose no safety concerns to the public <link 2>.
They also do not require that any GM derived product be labelled <link 2>.
As you can see, there are distinct differences between policy in the EU and USA.
LINKS
[1] http://www.defra.gov.uk/environment/quality/gm/
[2]
http://www.fda.gov/NewsEvents/Testimony/ucm161037.htm?utm_campaign=
Google2&utm_source=fdaSearch&utm_medium=website&utm_term=genetic%2
0modification&utm_content=10
Potential benefits of GM
“One might also ask a health expert to discuss why the British public, unlike that
elsewhere, is so resistant to GM food while it happily swills down alcopops.”
Steve Jones, BBC Trust Review of impartiality and accuracy of the BBC’s coverage
of science <link 4>
GM plants are produced for a variety of reasons, but I would like to talk about
diseases. World wide, crop losses due to disease account for significant financial
losses. As an example, I will look at the potato.
The history of the potato is plagued by disease. For example, the potato famine in
Ireland in the 1840s was caused by blight caused by a fungus called Phytophora
infestans. Globally, each year, this disease still causes £3.5 billion in losses[3].
Since there are few potato varieties (definition) that are resistant (definition) to
this disease, genes need to be found in other plants. Often the only way to get
these into the potato genome (definition) is by GM techniques.
?Another worry, due to global warming, is reduction in water availability.
Therefore, drought resistant crops will be necessary. This is a tough attribute to
get with plants. To make any difference, you often have to insert three or more
new genes. With traditional breeding techniques (i.e. non-GM), this can take a
long time. GM produces the same results, only faster.?
Often, benefits of GM focus on big corporations. However, I would like to
highlight one example that benefits the consumer: Golden Rice™. A clever
addition of three separate genes meant that the rice produced had higher
vitamin A content than traditional white rice <link 1>. Lack of vitamin A can lead
to many health problems, particularly in children who can become blind <link
2>. The idea behind Golden Rice™ is to provide a rice grain that has lots of
vitamin A to prevent these health related problems.
This is one of the potentials of GM; benefit to the consumer by creating more
nutritionally healthy food, although this is still a long way off!
LINKS
[1] http://www.goldenrice.org/
[2] http://whqlibdoc.who.int/publications/2009/9789241598019_eng.pdf
[3] http://www.tsl.ac.uk/lateblightqa.html
[4]
http://www.bbc.co.uk/bbctrust/assets/files/pdf/our_work/science_impartiality
/science_impartiality.pdf