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GENETICALLY MODIFIED FOODS
Genetically from the word ‘Gene’. Genes control the characteristics
that are passed from one generation to the next. Genes are copied
every time a cell reproduces and is made up from Deoxyribonucleic
Acids (DNA).
GM food is copying a gene with its code for a particular characteristic
and inserting it into another living organism. This will then be
reproduced in the new organism. Genetic engineers use enzymes to
do this.
Often done to improve crop yield, offspring, resistance to disease,
increased storage, resistance to chemicals.
Most come crops are oilseed rape, soya beans, cotton, kiwi fruit,
maize, sugar beet, potato and tomatoes.
Working on bacteria, fungi, animals and fish to grow faster, less fat,
disease resistance.
What are GM foods?
All living things are made up of genetic material.
Nature has always changed the genetic properties of
living things by mutation and natural selection.
Now modern scientists can change the
genetic make up of cells to change their
properties.
For example, genetic engineering could
allow certain characteristics of wild wheat
to be transferred to wheat grown as a
crop to make it more resistant to disease.
How are foods genetically modified?
Scientists use chemical ‘scissors’ to obtain the DNA or
gene they want to transfer. It could come from an
animal, a plant or bacteria.
They then place it into a plant cell.
The DNA then gets into the nucleus of the plant, and
new cells grow from the altered ones to make plants
with the new characteristics.
The DNA will have been chosen to pass on the feature
they want the new plant to have.
Gene taken from
bacterium that
produces a natural
insecticide
Added to wheat cells
Wheat that does not
need to be sprayed
against insects
Why are foods genetically modified?
Some genetic engineering is done for economic
reasons – the crop will grow bigger or faster and so
make more money.
GM crops may be useful to poorer countries if they need
less water, or are more resistant to pests and diseases.
Some genetic research is for medical developments
such as new vaccines or cancer treatments.
It may be possible to make biodegradable plastics
from plants to reduce the amount of fossil fuel we use
and help the environment.
Tomatoes, modified to contain
three times the normal amount of
vitamin A, may help prevent
cancer, scientists claim.
Genetically modified enzymes
Enzymes are proteins that speed up chemical
reactions such as digesting food.
Chymosin is an enzyme extracted from the
stomach of calves which is added to milk as rennet
to make cheese.
An equivalent enzyme can be made from
genetically modified micro-organisms such as
yeast.
This means the cheese that
is produced is suitable for
vegetarians and as a result
fewer calves are slaughtered.
Concerns about GM
• Pollen from GM crops mix with wild plants to
affect the ecology.
• New resistant microorganisms could develop
which could cause problems in plants and
animals.
• People become allergic to GM foods if allergens
from other plants inserted.
• Often GM crops are not fertile, so seeds from
current crop can’t be kept for following year.
You can only tell if it is a GM crop if it is stated on
the label.