MAY 26, 2021 9:00 AM PDT

Sterilizing Mosquitos with CRISPR to Control Disease

WRITTEN BY: Anne Medina

Mosquitos—including Aedes aegypti—facilitate the spread of bloodborne diseases the world over and cause hundreds of thousands of deaths a year according to the World Health Organization, making control of the mosquito population a critical public health objective. Using CRISPR-Cas9 gene editing, researchers from the University of California at Santa Barbara have presented a new target for sterilization of male Aedes aegypti in Proceedings of the National Academy of Sciences.

By flooding the breeding population with genetically manipulated sterile males, scientists hope to outcompete fertile wild males by sheer volume. This method—called the ‘sterile insect technique’—has effectively controlled populations other species, including the Mediterranean fruit fly that plagued California agriculture. Since only female mosquitos bite, a rash of additional males wouldn’t act as vectors for human disease.

Previous SIT experiments with Aedes aegypti have been limited by the techniques used to sterilize the males—namely radiation and chemical exposure, which had the unintended side effect of making the ‘trojan horse’ males weaker and less successful at mating.

The PNAS study is the first to use CRISPR-Cas9 to target male Aedes aegypti, authors say, rendering them infertile by knocking out a gene expressed in the testes. Lab experiments in which infertile males outnumbered their wild-type cousins by 5:1 reduced female fertility by 50%, while at a ratio of 15:1 female fertility plummeted 80%.

The authors emphasize that suppressing a single generation with the sterile insect technique wouldn’t significantly impact population numbers, even if fertility is reduced to 20% of normal levels—SIT must be repeated in successive seasons.

Other studies have targeted genes common to male and female Aedes aegypti, including a 2020 PLOS experiment that resulted in flightless females unable to mate or spread disease. Homozygous males were, however, still able to fly and pass on their defective genes to subsequent generations.

About the Author
  • Anne is a science writer based in the Southeastern United States, one of the unsung biodiversity hotspots of the world. She channels her passion for animals and ecology into her work as a science communicator, making the latest discoveries accessible and engaging for the public.
You May Also Like
JAN 31, 2021
Cell & Molecular Biology
Humans Drank Milk Long Before Their Bodies Could Tolerate It
JAN 31, 2021
Humans Drank Milk Long Before Their Bodies Could Tolerate It
Scientists and archaeologists have long sought to learn when humans started consuming milk. They have tried to use indir ...
FEB 28, 2021
Cell & Molecular Biology
How a Slime Mold with no Brain Can Remember Things
FEB 28, 2021
How a Slime Mold with no Brain Can Remember Things
Our past experiences help us navigate future obstacles, and it seems that even organisms without a brain have that skill ...
MAR 14, 2021
Cell & Molecular Biology
Modern Animals Still Have Similarities to Our Weird Ancient Ancestors
MAR 14, 2021
Modern Animals Still Have Similarities to Our Weird Ancient Ancestors
Recent research involving ancient marine animals shows how humans and other animals still carry some of those animals' c ...
MAR 31, 2021
Plants & Animals
Spring Winds Following Warmer Winters Cause Mass Jellyfish Strandings
MAR 31, 2021
Spring Winds Following Warmer Winters Cause Mass Jellyfish Strandings
Beachgoers are certainly not fond of jellyfish in the water, but seeing hundreds of them wash ashore is an interesting a ...
APR 05, 2021
Microbiology
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
APR 05, 2021
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
Many types of bacteria often live harmlessly in and on animals and humans, but some bacteria pose a threat. Salmonella b ...
APR 20, 2021
Genetics & Genomics
The History of Lettuce Domestication Told Through DNA
APR 20, 2021
The History of Lettuce Domestication Told Through DNA
The more we know about the genetic history of food crops, the more prepared we'll be to maintain their growth through en ...
Loading Comments...