Malaria mosquitoes eliminated in lab by creating all-male populations

The birth of a population of malarial mosquito males only: surprising results of a study just published in Nature Biotechnology

Controlling mosquitoes is a vital part of any integrated strategy to fight malaria. Target Malaria team at the laboratory of Professor Andrea Crisanti at Imperial College London has been working on developing novel genetic technologies as a tool to fight the disease. This strategy focuses on decreasing the number of female vector mosquitoes in a population because only females bite and transmit the disease, and their number usually determines population size and transmission rates.ine possono trasmettere la malattia ed il loro numero determina la dimensione della popolazione.

Manipulating the male-to-female ratio of mosquito has been a long-sought goal for vector control. Previously, the Crisanti Lab generated a strain of mosquitoes that produces predominantly males, but the modification was passed on to only 50% of the progeny. Now, the team moved the technology further by generating a driving male-biased sex distorter that is inherited to nearly all offspring and could eliminate caged populations of Anopheles gambiae mosquitoes. This is the subject of a paper just published in Nature Biotechnology, entitled “A Male-biased Sex-Distorter Gene Drive for the Human Malaria Vector Anopheles gambiae” which lead author is Alekos Simoni, now the Scientific Manager of Polo GGB.

The modification works by using a DNA-cutting enzyme to destroy the X chromosome in the mosquito sperm, leading to predominantly male offspring (as females require two Xs while males require an X and a Y). This was then coupled to a gene drive targeting a conserved site in the doublesex gene to allow it to spread through a population from a very small initial frequency without resistance, showing that it could have huge potential to control malaria-carrying mosquitoes in the field.