Mutant bugs released to fight disease

Aedes aegypti: The female mosquito bites for blood, which she needs to mature her eggs. © Getty

Is it wrong to release modified mosquitoes into the wild? Supporters say genetically altered insects could eradicate deadly diseases, but opponents are warning of dangerous consequences.

Tropical diseases carried by mosquitoes kill a million people every year. So, it may seem strange that a laboratory wants to release 750 million of these insects into the skies of Florida, in the United States. But these are no ordinary bugs. They have been genetically programmed to destroy their own species.

This is the latest move in the fight against mosquito-borne diseases like malaria, dengue, and yellow fever. Half the world lives with the risk of infection and billions of dollars are spent every year on new drugs, pesticides, and public health measures. But the drugs are losing their potency and the mosquitoes are growing resistant to the pesticides.

Synthetic biology may offer the knock-out blow. This branch of genetic engineering allows scientists to edit the mosquito’s DNA and introduce a “self-limiting” gene. This artificial DNA sequence kills the biting females whilst leaving the modified males to spread the auto-destruct gene through the wild population.

Authorities have approved the scheme in Florida, but environmental groups are furious, calling it a “Jurassic Park experiment” that will unleash a “mutant bug” into the ecosystem. Many argue that the modified mosquito may have unforeseen consequences.

To protect against this scenario, bioengineers have built kill switches into some of their creations. This mosquito contains a fluorescent gene, making it easier to identify.

So, is it wrong to release genetically modified mosquitoes into the wild?

Playing god

Yes, this is a dangerous experiment with too many unforeseen consequences. Nature is a complex, interconnected system where small changes can have major negative effects.

No, people’s fears are based on science fiction and disaster movies, not hard evidence. There is no proof it will harm other species – but it will save thousands of lives lost every year to dengue and yellow fever.

You Decide

  1. Do we have the right to put an end to a species?


  1. Design your own genetically modified super-insect. Then draw a diagram of it, explaining how it will improve the world.

Some People Say...

“Mosquitoes are the greatest mass murderers on planet Earth.”

Katherine Applegate, American science-fiction writer

What do you think?

Q & A

What do we know?
Most agree that the GM debate taps into long-held fears about the dangers of new technology interfering with the natural order of things. Mary Shelley’s Frankenstein drew on these anxieties, which go back to Prometheus, the Greek hero who was punished for stealing fire from the gods.
What do we not know?
Are we playing God with nature? Religious traditions describe our role as guardians of the Earth, which means we have a duty to respect and conserve our environment. Some argue that modifying genes to kill off a species goes against this duty. But others ask where we should draw the line. Are pesticides and drugs also a form of playing God? And does our responsibility to protect human life come above preserving the natural world?

Word Watch

Genetically programmed
The modified variant of the Aedes aegypti mosquito was designed by the biotech company Oxitec and is known as OX5034, or the “Friendly Mosquito”.
Carried and passed on by mosquitoes.
There is no vaccine for dengue fever, which is on the rise across much of the world, driven by climate change and urban poverty. It is also known as “breakbone fever” for the extreme muscle pain it causes.
Chemicals used to kill pests, including insects, rodents, and weeds. Pesticides are used in public health to kill carriers of disease, such as mosquitoes.
Synthetic biology
In 1974, scientists inserted foreign DNA into a mouse, making the first GM animal. But only in the last decade has technology advanced sufficiently to use man-made DNA to make new synthetic organisms.
Jurassic Park
In the 1993 Steven Spielberg blockbuster, every precaution is taken to prevent a park of genetically reanimated dinosaurs from running wild. But in the words of one character, “life will find a way” – and events spiral disastrously out of control.
Not anticipated or predicted.
Kill switches
Some are dependent on nutrients not created in nature, whilst others contain a so-called “Deadman” gene, which causes the organism to self-destruct when it detects a change in its environment.
Fluorescent colours are very bright and can be seen in the dark.

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