"Genetic engineering increases our options
for non-chemical control of pests"
In 1953, Watson and Crick discovered that DNA present in all cells
contains a code that is used by cells as a "recipe" for
how an organism will function.
In all organisms, the code is made up from a four letter alphabet
(A, C ,G, T) which usually contains between 1,000 and 100,000 letters.
The entire recipe, called the genome, may contain between 4 million
(simple bacteria) and 3 billion (human) letters or more. The genome
contains many different types of genes which carry out varied functions.
For example, the colour of your eyes are determined by specific genes.
How does genetic engineering work?
One of the great discoveries of this century is that DNA from
any organism will function if it is properly transferred into any
other organism! A whole new technology has arisen out of this single
Genetic engineering is the process whereby genes which carry out specific
tasks in a cell are cut from one organism and glued into another.
This confers a new ability on the organism that has received the gene.
There are a number of tools required for
DNA is cut using restriction enzymes.
Genes (groups of DNA) are transported around on plasmids
Ligase is an enzyme that glues DNA particles together
Genes which have a trait wanted for another
organism are cut using a restriction enzyme
These genes are inserted into plasmids by
first cutting the plasmid with restriction enzymes
These genes are inserted into plasmids by first cutting the plasmid
with restriction enzymes
The gene is now a part of the plasmid.
The plasmids are often located in a bacteria like Agrobacterium. Once
the plasmid in the bacteria has the new gene, they are cultured to
make many copies of the plasmid and then placed next to plant cells.
Plasmids of Agrobacterium have the property
of being able to jump from one cell to another, and so move into the
The plant cells are grown into mature plants using a process called
These plants will contain the new gene in their
cells which will give them the new, desired trait.
The centre row of potatoes has been genetically engineered to
resist pest attack. The others have not.
How is genetic engineering use in pest control?
For pest control, different types of genes are inserted into plants
to give them some ability to fight off or avoid pests.
*Genes are inserted which produce a natural or synthesized toxin to
kill or ward off pests (See section on IPM - Integrated Pest Management).
*Genes are inserted which contain a specific resistance gene which
makes organisms immune to the pest (See IPM - Integrated Pest Management).
*It is also possible to insert genes into crop plants which confer
resistance to a herbicide which would have once killed the plants.
The advantage of this is one herbicide can be used to control all
the weeds in that crop.
Engineering is used as a pest control strategy because
1. it can replace some pesticides
2. it is safe for humans and the environment
3. it is inexpensive in the long term
Engineering is not always used because
1.It is expensive to set up (cost of research)
2. it takes a long period of research to make sure that the genetically
engineered organism is safe to release
3. pests are controlled using other control strategies
Go to the Careers sectionto meet some people
who are looking for ways to control pests using Genetic Engineering.