This appears promising. The good news though is that pressure continues on the mosquito populations world wide as resources continue to be applied against it.
This method continues the effort to bring about collapse by biological means.
It remains a tough problem. Imagining method has been simple enough for years. Yet here we are trying another avenue. .
Gene editing wipes out mosquitoes in the lab
Researchers have used gene editing to completely eliminate populations of mosquitoes in the lab.
The team tested their technique on the mosquito Anopheles gambiae, which transmits malaria.
They
altered part of a gene called doublesex, which determines whether an
individual mosquito develops as a male or as a female.
This allowed the Imperial College London scientists to block reproduction in the female mosquitoes.
They want to see if the technology could one day be used to control mosquito populations in the wild.
Writing in the journal Nature Biotechnology, Prof Andrea Crisanti and colleagues report that caged populations of Anopheles gambiae collapsed within 7-11 generations.
Dr
Crisanti said: "2016 marked the first time in over two decades that
malaria cases did not fall year-on-year despite huge efforts and
resources, suggesting we need more tools in the fight."
The
approach falls within a category of genetic engineering known as a gene
drive. It describes technologies that spread a gene or particular suites
of genes through a population.
The researchers used the
gene editing technique known as Crispr to modify a part of the doublesex
gene that is responsible for female development.
Males who carried the modified gene showed no changes, and neither did female mosquitoes with one copy of the modified gene.
However,
female insects with two copies of the altered gene showed both male and
female characteristics, did not bite and did not lay eggs.
Resistance overcome
As the modified gene - which confers female infertility - spread, the caged populations crashed.
However,
previous attempts to use this approach in mosquitoes ran into problems:
the insects developed resistance to the genetic modification.
This
occurred because targeted genes developed natural mutations that
allowed them to continue functioning, and these mutations were then
passed down to offspring.
However, the doublesex gene is highly
"conserved", which means that random mutations are for the most part
lethal to the organism.
In this way, the scientists were able to sidestep a potential source of resistance.
The
researchers now want to test the technique on larger populations of
mosquitoes confined in more realistic settings, where competition for
food and other ecological factors could affect the outcome.
Prof
Crisanti commented: "There is still more work to be done, both in terms
of testing the technology in larger lab-based studies and working with
affected countries to assess the feasibility of such an intervention.
"It
will still be at least 5-10 years before we consider testing any
mosquitoes with gene drive in the wild, but now we have some encouraging
proof that we're on the right path.
"Gene drive solutions have
the potential one day to expedite malaria eradication by overcoming the
barriers of logistics in resource-poor countries."
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