Maternal effect dominant embryonic arrest (Medea) is a selfish gene composed of a toxin and an antidote.
These findings have dramatic implications for the control of insect-borne diseases such as malaria and dengue fever.
Medea, which has been found in nature only in flour beetles, is an example of a selfish gene that has been simulated in the lab and tested in the fruit fly Drosophila melanogaster.
The toxin was a microRNA that blocked the expression of myd88, a gene vital for embryonic development in insects.
In lab trials where 25% of the original members were homozygous for Medea, the gene spread to the entire population within 10 to 12 generations.