Genetically modified mutants 'safe for release' into the wild

'Underdominance' experiment on remote island

Remorseless German boffins say that the time may now be ripe for scientists to begin release of "transgenic individuals into populations". Concerns that this might result in those populations being completely replaced by the superior lab-developed individuals can be addressed, they say, by the use of cunningly selected mutants.

Rather than some kind of sinister play to replace unsatisfactory human beings with superior lab-grown varieties, this is actually aimed at helping people – for instance by wiping out the terrible menace of mosquito-borne malaria, one of the most potent threats to human health around.

According to the geneticists of the Max Planck Institute for Evolutionary Biology in Plön:

Populations containing mutants with heterozygote disadvantage develop into one of two stable states. These mutant types therefore seem to be well-suited for the safe release of genetically modified organisms. After all, as soon as sufficient numbers of mutants exist in the environment, these replace the natural variant in a local population. If such genes are joined to resistance genes to combat pathogens, mosquito populations could be rendered resistant to malaria, for example. By releasing the wildtype at a later stage, the transgenic animals can therefore also be removed again more easily from the environment. In population genetics this is known as underdominance.

In essence, the cunningly crafted mutie mosquitoes would replace their wild brethren and so extirpate malaria in that area as it would no longer be able to propagate itself. Then things could be put back as they were before, preventing the modified mosquitoes from taking over the world.

"Genetically modified organisms must not be allowed to spread uncontrollably," say the Max Planck researchers, reassuringly.

The mutant heterozygote method would be a lot more effective than current ploys in which modified mosquitoes etc are released, as these use infertile males only and so struggle to achieve lasting effects. The new German mutant plan would allow the intruder species to multiply, but still be eliminated once their work was done.

In traditional style when speaking of creating artificial monsters in a completely safe experiment, the plan is to do so at first on a remote island – just to be sure.

“Nevertheless, the fitness of the transgenic animals, the population sizes, and the migration rates must be known. These factors can most likely be determined for release experiments on maritime islands,” says the Max Planck Institute's Arne Traulsen. ®

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