Hybridization and genetic modification are different

Many people interchange the terms "genetically modified" and "hybrid."  The two are very different.  Genetically modified food has only been existence in the past couple of decades.  Hybridization has gone on since before recorded history.  In terms of hybridizing I always think of Luther Burbank, probably the most prolific hybridizer in human history.  The man had a green thumb.  He created the seedless grape, the Burbank potato (used by McDonalds) and hundreds of other things, decades before genetic engineering.

How does this technology (i.e., genetic modification) differ from what went before?

Farmers have been engaged in what we might term "traditional genetics" for thousands of years. They have long understood that like begets like, favouring the seed from plants with the most desirable characteristics.

New plant types have also arisen by cross-breeding closely-related species. This is how we got oil seed rape and bread wheat.

But way genes are passed from one generation to the next through sexual reproduction is something of a lottery.

Scientists have tried to speed things up by exposing experimental plants to chemicals and radiation. This has the effect of producing hundreds of mutations among the genes. Some of these may be useful, others will not and the plants will be discarded.

Genetic engineering, on the other hand, is more specific. It allows scientists to select a single gene for a single characteristic and transfer that stretch of DNA from one organism to another - even between different species.

An example of genetic engineering is the FlavrSavr tomato developed by Calgene. When tomatoes ripen, a gene is triggered to produce a chemical that makes the fruit go soft and eventually rot.

Scientists have now modified the gene which has the effect of "switching off" the chemical. As a result, the FlavrSavr tomato softens more slowly, meaning it can stay longer on the vine to develop a fuller taste. Its longer shelf life also reduces waste.

When was GM food invented?

The first transgenic plant - a tobacco plant resistant to an antibiotic - was created in 1983. It was another ten years before the first commercialisation of a GM plant in the United States - a delayed-ripening tomato - and another two years (1996) before a GM product - tomato paste - hit UK supermarket shelves.

1996 was also the year that the EU approved the importation and use of Monsanto's Roundup Ready soya beans in foods for people and feed for animals. These beans have been modified to survive being sprayed with the Roundup herbicide that is applied to a field to kill weeds.

This soya, together with GM maize, is now used in a variety of processed foods on sale in UK shops. The products range from crisps to pasta.

A genetically-engineered version of the milk-clotting enzyme chymosin is also used in cheese-making.