How can we make mosquitoes go extinct?

You probably learned in school that genes propagate following Mendel’s Laws. According to these, all sexually reproducing organisms (including you) get 50% of their genetic information from their mother and 50% from their father. However, there are a few genes that do not follow Mendelian inheritance rules. They are known as selfish genetic elements,  since they manage to cheat the system and propagate to the offspring with a chance higher than 50%.

These selfish genes occur naturally and they are present in all living organisms. And finally, after decades of research, we humans have figured out how to use them in our advantage. Nowadays, we are able to couple a “normal” gene with a selfish genetic element, and thus making the normal gene spread to all the population of a species. This is called a gene drive.

 

Image licensed under CC-BY-SA 4.0. Modified from Wikimedia Commons.

OK cool, but how is this gene drive thing going to kill any mosquitoes at all?

If used creatively, a gene drive can make disappear a fast-reproducing species in just a few years. For example, we could introduce a gene in a single male mosquito that makes all of his offspring to be male as well. All of them. And when these new male mosquitoes mate with other females, all the offspring will be male also. This would go on until there are no females left, so the whole species would effectively become extinct.

If this sounds like science fiction, you will be surprised to learn that these mosquitoes already exist! In September 2018 a new study was published in the journal Nature that proved these concepts in caged mosquitoes. When introducing a few male “gene drive mosquitoes” into a healthy population (wild males and females), all the mosquitoes disappeared in only 7-11 generations.

Scary right? We have the power to eliminate a whole species but… with great power comes great responsibility. What if this technology irreversibly damages the environment? Could artificial gene drives jump into other species and make them go extinct too? Maybe the consequences end up being even worse for us than the existence of mosquitoes themselves!