Infertile male insects can be genetically hacked to make females infertile through mating.
Scientists at the US Army Research Laboratory discovered a new method to genetically modify the mosquito Aedes Aegypti. This can be used to decimate wild populations and prevent diseases such as Zika and dengue spreading.
According to research published in PNAS, the genetic alteration rendered males infertile. However, male mosquitoes can transfer infertility to females by mating with them.
In a press release, James Burgess (a DEVCOM program manger for the Army Research Laboratory) stated that this is another exciting example of synthetic biology tools proving unparalleled utility. It's a precise increase in chainsaw use to scalpel that leads to the right biochemical outcome, which could significantly reduce the number of very infectious mosquitoes.
The system must work if the females are separated from the males in order to make it work. Researchers discovered that females had to mate with many different mosquitoes in order to become infertile. After being kept in a cage with only genetically hacked males for four hours, fertility rates dropped to 20% among the females.
Craig Montell, University of California Santa Barbara biologist, and coauthor of the study, stated in a press release that all of the females were sterile. This confirms that male fertility can be suppressed by female fertility, even if they don't produce sperm.
This increased number was associated with longer exposure to males. However, this raises questions about real-world feasibility as both gene-hacked males and wild-type healthy males will be competing for the same mate out in the wild.
Montell explained that even though wild females may mate with genetically-hacked males and a wild population of Aedes aegypti could recover from an 80 percent decline in fertility, the challenge is that wild females can still mate with these gene-hacked males.
This does not necessarily mean that infertility alterations do not work. However, repeated drops of males would be required to ensure that this mosquito gene-hacking technology is successful in reducing the population and making a difference in disease transmission.
These logistical issues also hampered a controversial Florida Keys experiment where Oxitec, a biotech company, released similar gene-hacked mosquitoes. Local communities were furious at the Oxitec experiment for several reasons. It involved live release which was a completely different situation than the new lab experiment. It does show the dangers of gene-hacked bugs being released into nature by Army research.
READ MORE: Genetic editing could make mosquitoes infertile and reduce disease spread [US Army Research Laboratory]
More about mosquitoes: Residents furious at the release of 500 million gene-hacked mosquitoes