Science - November 1, 2012

Smart cut-and-paste work can reduce GM risks

The location of DNA in the genome affects risks of GM crops. Less chance of 'leaking out'.

Transgenes from GM crops can end up in wild relatives of these crops via crossing. But the chances of this happening very much depend on where in the genome of the plant the new gene is introduced, according to research at Plant Breeding.
An ecological risk analysis is a standard procedure for the approval of new GM crops. The key consideration is whether the gene introduced into the GM crop can cross over to wild plants, giving these plants so many advantages that the natural ecosystem is affected.
Wageningen PhD researcher Brigitte Uwimana tested this by crossing cultivated and wild lettuce varieties and then crossing their offspring several times with wild lettuce varieties. She used markers to find out which DNA fragments of the cultivated lettuce ended up in the genome of the wild lettuce.
The genome analysis showed that some pieces of genome were advantageous to the plant while other pieces were selected out. Therefore, to produce a safe GM lettuce you need to introduce the gene in those parts of the genome which lower the fitness of wild varieties, says Smulders. This minimizes the chances of such genes 'leaking' into the environment.
The test using the lettuce - not a GM crop - showed that 'strong' and 'weak' spots can be pinpointed in the genome, and that you can take these into account during genetic modification, says Smulders. The Netherlands Commission on Genetic Modification, which advises the government on the risks of GM crops, will need to assess how big the safety benefits are, while breeders will have to find out whether such benefits are easy to achieve and to weigh these against the costs.' Smulders published the proceedings of the research, which was funded by NWO, in this month's Theoretical and Applied Genetics.

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