Enjeux - GMOs, a stormy debate

GMOs, a stormy debate

Sowing, harvesting and exchanging are fundamental rights of countries and individuals. After more than 15 years of controversy over GMOs, scientists, farming professionals, associations and consumer groups continue to debate an ever-stormy topic: can we modify the genome of plants, animals or any living organism, and in which conditions?

THE CONCEPT

Definition

A GMO, short for genetically modified organism, is a living animal, plant or micro-organism produced through a new selection technique called transgenesis. Using this technology, pioneered roughly 30 years ago, breeders first succeeded in identifying genes that are advantageous for the species they are seeking to improve – corn and soya bean, for example. They then managed to isolate this gene and, using several techniques, introduce it in the genome of the species concerned , thus creating a new variety. The added gene, which can come from the same species or another species, gives the variety a new characteristic, referred to as “genetically improved”. Man has always sought to improve varieties and species by crossing “improvement” genes. Older methods were simply a great deal more empirical.

Not to be confused: OGMs and biotechnology

Simply put, a GM variety features a new characteristic carried by a new gene introduced into its genome. Scientists refer to this gene as a “trait”. Gene building is not about assembling; rather, it is an ongoing flux of modifications, insertions and transfers. We now talk about the “fluidity” of the genome, which becomes a part of a wider ecosystem extending to the population of individuals and to relationships with the environment.  This is the systemic vision of genomics that dominates today, with its different layers of organisation and exchanges.

More generally, biotechnologies group an entire set of recent technologies,  one of which is the creation of GM varieties, alongside molecular marking, knowledge of the genome, and so on. The purpose of these new tools is to facilitate and accelerate the work of breeders using conventional selection methods.

Advantages of GMOs

So why are scientists and seed manufacturers so interested by GMO technology? Conventional selection consists essentially in crossing two varieties, A and B, through several generations to obtain a third variety that retains the main characteristics of A but with a very precise trait from B (disease resistance or higher protein content, for example). The problem is that it takes a long time to obtain the sought-after result (ten years to create a new variety of wheat) and that a high number of individuals have to be crossed. Also, the trait-bearing gene from variety B that the breeder wants to introduce is often accompanied by unwanted traits.

Creating GM varieties enables us to precisely identify and isolate the sought-after gene without the unwanted gene cocktail in tow. GM engineering is also faster to implement and can be used to introduce a gene from another species. For example, a gene from the Bacillus thuringiensis bacterium used in insect control in organic farming was introduced into corn to make it resistant to predatory moths, a serious pest for corn farmers.

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