A female Aedes aegypti mosquito can carry potentially deadly diseases as dengue fever
Modified mosquitoes could help eradicate the wild populations that spread many diseases. Similarly, crop pests that are resistant to pesticide could be modified to wipe out populations of pests. But the gene drive technique could also be misused by terror groups to threaten human populations. Reuters

The US National Academy of Sciences has initiated a review of the controversial gene drive technology as a group of 27 leading geneticists called for strict controls to limit risks from an unintended release or deliberate misuse of altered organisms.

Synthetic gene drives, using a simple gene editing system called CRISPR, can, for example, alter the traits of mosquitoes or invasive cane toads, and even eradicate the species. The technology offers tremendous benefits to human health and crops.

But potential for misuse by terror groups or accidental release from labs is high, as these "super" organisms can spread rapidly, and cause health and environmental disasters.

Some experts like David Gurwitz of Tel Aviv University believe it could be used as a terrorist bio-weapon to spread lethal toxins within a population. He has called for classifying the precise instructions for making gene drives, as with nuclear weapons.

Gene drives induce changes in traits that are fast inherited in a population of species, in a few generations, much like a nuclear chain reaction that sets off once triggered.

A modified gene introduced in one fly can, in a few generations, transmute practically every other fly in the breeding population as against natural genetic evolution which takes a longer time for a trait to spread widely.

Kevin Esfeldt, a gene-drive expert at the Wyss Institute at Harvard Medical School in Boston, explains that gene drives allow a modified gene to jump from one chromosome to another within the same individual so that eventually all of the sperm or eggs of the animal carries the GM trait, not just half.

None of the offspring can escape an introduced GM trait.

Wipes out wild genes
While this can help eradicate parasites that spread diseases, or kill invasive species and crop pests, the mutation is irreversible.

The wild genes cannot compete with modified ones, natural selection would be turned on its head and decisions made by some researchers could end up permanently rewriting the genomes of entire wild populations.

It is in this context that the research teams from the Wyss Institute and University of California, San Diego (with published work on gene drives) have assembled the group of genetic engineers and fruit fly geneticists, to unanimously recommend a series of pre-emptive measures to safeguard gene drive research.

"They have tremendous potential to address global problems in health, agriculture and conservation but their capacity to alter wild populations outside the laboratory demands caution," the scientists say.

The researchers have called for a public debate on the technology, saying openness and transparency, not classifying the information, are the best defence against misuse of gene drives.

The letter was published online in Science Express journal.

UK scenario
In the UK, the Synthetic Biology Leadership Council, which is overseeing the government's strategy for fostering the development of the nascent science of synthetic biology, and the Advisory Committee on Releases into the Environment (Acre) are expected to include gene drives on the agenda, writes The Independent.

A Defra spokesperson said: "We have never received an application to release a GM organism based on so-called 'gene-drive' technology into the environment in the UK – any such application would be subject to a rigorous, independent risk assessment."

Groups like GeneWatch UK fear that de-regulating gene-editing techniques would leave gene drives open to widespread use (and misuse) without proper monitoring.

Experts have in the recent past voiced concern over the runaway effects of gene editing from the CRISPR technology. Work on human embryos have raised ethical fears about superhumans and designer babies with experts warning that much about gene variants remains unknown.