Genetically modified mosquitoes to help fight malaria

British researchers claim they have genetically modified mosquitoes to become sterile and thus check the spread of malaria.

A team of researchers from the Imperial College London modified the gene of the malaria-spreading mosquito to introduce traits that disrupt egg production in females .

They then used a technology called 'gene drive' to make sure that the gene is passed down at an accelerated rate to offspring, thus making the whole mosquito population sterile over time.

The scientists worked with the mosquito species Anopheles gambiae which spreads malaria in sub-Saharan Africa, where 90% of the deaths occur.

Malaria infects more than 200 million people each year and causes more than 430,000 deaths, according to studies.

If it works in the field, this experiment, first reported in the journal Nature Biotechnology, could eliminate or drastically reduce the malaria-carrying species in years. In the lab the gene for infertility was passed on to more than 90% of both male and female offspring.

"It will be at least 10 more years before gene drive malaria mosquitoes could be a working intervention," said Professor Austin Burt from Imperial's department of Life Sciences.

The gene was modified using CRISPR/Cas9 endonuclease, a type of DNA-cutting tool that can target very specific parts of the genetic code.

The technique uses recessive genes, so that many mosquitoes will inherit only one copy of the gene. Two copies are needed to cause infertility, meaning that mosquitoes with only one copy are carriers.

Last month, US scientists had claimed they genetically modified the Anopheles stephensi -- the species that spreads malaria in India -- so that they resist infection.

That experiment introduced a "resistance gene" into the mosquito's gene so that they cannot pass on the malaria parasite when they bite people. The trait would be passed down the generations when the GM mosquitoes mated.