Every so often, a scientific development appears with an immense potential for good, but at the same time it also carries great risks if misused, either accidentally or deliberately. So it is with a technology called “gene drives” which is a means of spreading genetic traits rapidly through a population of insects or other kinds of fast-breeding organisms, rather like a virus. It “supercharges” genetically modified genes so that they defy the normal rules of inheritance. Normally, GM traits would not spread within a population of wild insects unless they impart a great evolutionary advantage. But when attached to a gene-drive DNA “cassette”, practically every individual in a breeding population will eventually end up being a GM organism.
Scientists are now waking up to the considerable practical possibilities that the technology presents. There are three areas where gene drives could be a force for good.
The first is in human health, particularly for insect-borne diseases such as malaria or yellow fever, carried by mosquitoes. It is possible to envisage gene-drive modifications to the mosquito, such as making all offspring male, which could lead to a population crash. This would curb the transmission of some of the world’s most devastating tropical diseases.
A second use is in combating important crop pests, again by introducing gene-driven genetic elements that lead to a population crash. The third area is environmental conservation, notably in fighting invasive species, such as rats on remote islands inhabited by ground-nesting birds, or the cane toads of Australia, which are wrecking the indigenous ecosystem.
However, the power of gene-drive technology to accelerate the spread of GM traits also introduces immense potential hazards. The most obvious danger is some kind of accidental escape from a laboratory where gene drives are being developed, unleashing an organism that could potentially spread uncontrollably in the wild with untold consequences.
More serious is the possibility that either a rogue state or a terrorist cell with access to a genetics laboratory might decide to generate a gene-drive organism that could pose a threat to human health or to economically important livestock – just think of the damage to Britain’s dairy and beef industries from the last foot-and-mouth epidemic.
As one concerned scientist has remarked, if gene drives can be used to make mosquitoes that are unfit for carrying the malaria parasite, it is conceivable that someone, somewhere could use them to design GM mosquitoes that can deliver lethal bacterial toxins to humans.
How can we guard against this possibility? The answer must be total transparency, rather than secrecy and data suppression. It is frankly not possible to prevent this technology from being discussed and researched by civilian scientists, and so the information cannot be classified.
The best defence against the nefarious use of gene-drive technology will be to make everyone aware of its potential, which means that counter-measures and safeguards can be built in and constructed before anyone tries to build a terrorist bio-weapon based on the technique.
Unlike nuclear devices, genetic bio-weapons would be relatively cheap and easy to make, requiring none of the great state infrastructure needed for the atomic weapons of mass destruction. So the most secure way to defend ourselves against these bio-weapons is for all scientists and governments to be as open about the technology as possible and for all of us to stay alert and informed.