Gene drivesThree ways synthetic biology could annihilate Zika and other mosquito-borne diseases

By Andrew Maynard

Published 25 July 2016

There are tried and tested approaches in the arsenal of weapons against the mosquito-borne disease, but to combat Zika and other mosquito-borne disease, more is needed. Gene drives, synthetic biology-based genetic engineering techniques, offer one solution by reengineering mosquitoes or obliterating them altogether. Yet we still have only the vaguest ideas of how the systems we’re hacking by using gene drives actually work. It’s as if we’ve been given free rein to play with life’s operating system code, but unlike computers, we don’t have the luxury of rebooting when things go wrong. As enthusiasm grows over the use of synthetic biology to combat diseases like Zika, greater efforts are needed to understand what could go wrong, who and what might potentially be affected, and how errors will be corrected.

In just a few short weeks, Zika has shot from being an obscure infection to a headline-hitting public health disaster. The virus is spreading rapidly across the Americas (and potentially beyond), is suspected of being associated with birth defects that affect brain development and currently has no specific vaccine or treatment.

Understandably, scientists are scrambling to respond to what the World Health Organization has called a “Public Health Emergency of International Concern.”

In the arsenal of weapons against the mosquito-borne disease, there are tried and tested approaches that include the liberal application of insecticides and repellents, widespread use of mosquito nets and elimination of breeding sites.

Yet to combat Zika and other mosquito-borne disease, more is needed. Which is why scientists are increasingly turning to emerging technologies such as synthetic biology for solutions.

The joke goes that if you get ten synthetic biologists in a room together, you’ll get ten different explanations of what they do. After all, synthetic biology is a young and rapidly evolving field. But underneath this lack of clarity lies a clear and profound shift in our technological capabilities — the ability to “upload” genetic code to computers, edit and manipulate it, and then “download” it into living organisms.

In effect, we’ve discovered how to hack biology — how to code in DNA and computer-design living things.

It’s early days yet — biology is complex and messy and doesn’t follow the same rules as computer code. But increasingly, scientists are learning how to use synthetic biology to change how organisms operate – including insects that carry dangerous human diseases, such as Zika.

Turn off a gene and goodbye mosquitoes
Using synthetic biology-based genetic engineering techniques, the British company Oxitec (owned by U.S.-based Intrexon Corp) has successfully added a genetic switch to Aedes aegypti mosquitoes, the species that carries dengue and Zika. As long as the insects are fed the antibiotic tetracycline, the switch remains off and the bugs are fine. But remove the drug, and the switch is activated — preventing genes from working, and ultimately killing the mosquito.

It’s a trait that enables the controlled decimation of wild mosquito populations.