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Genetically Modified (GM) Food


Plants have been genetically modified to produce pest resistant crops helping farmers and improving the general quality of crops for the consumers.

For example tomatoes have been produced containing genes which result in them remaining fresh for much longer than usual after picking. This makes it much easier and cheaper to transport them from the grower to the shops and they have a much longer shelf life.

Genetic modification of oilseed rape has opened up the door to an alternative renewable oil source.

Oil is used as a fuel, food and lubricant. It is used extensively in the manufacture of detergents, leather goods, cosmetics, paper, paints and textiles.

Petroleum has been used as a source for oils for many years but growing concerns about this fossil fuel running out in the future have led scientists to explore alternative avenues.

Rape, is the bright yellow-headed flower crop we often see growing in fields. However, the oil it produces is a long-chained fatty acid of 22 or more Carbon atoms. This is too heavy or long for many uses but okay for cosmetics.

However, a plant called Californian Bay makes oil with fatty acid chains of 10-14 carbon atoms. These are great for making detergents from. The plant contains a gene that codes for Thioesterase the name for this short-chained oil.

How can we make this oil in our easy to grow local rape seed oil crops?

Step 1.

The Thioesterase gene is identified and cut out of the Californian Bay plant.

Step 2.

It is then inserted into a special Ti Plasmid (Tumour inducing) from a bacterium. This plasmid is then inserted into a Vector Agrobacterium tumefaciens. This bacteria and plasmid will invade plant cells and cause them to divide rapidly making a callus or ball of cells as a swelling on the plant.

Step 3.

The Agrobacterium and the Ti plasmid insert the gene into the rapeseed cells. They quickly invade the cells and swellings grow on the plant. These transformed rapeseed cells are then grown using tissue culture into whole new plants. Every cell contains the new thioesterase gene and produces the oil.


The entire process takes between 5 and 10 years.

NB. Instead of using Agrobacterium we could of used ballistics to shoot the gene into cells using a special gun.

So why are many people worried about GM foods?

A. Herbicide resistance genes could be transferred into weeds.

B. Disease causing organisms could escape into the environment.

C. Toxins produced by GM crops could build up in insects and then herbivores in the food chain.

D. Breakdown of GM crop tissue could release toxins, and change soil ecology.

E. Pollinating insects could be damaged.

F. Humans may have allergic reactions to the new foods.

G. GM food may transfer antibiotic resistant genes to bacteria that will then infect humans/animals.