Researchers in Coleen Murphy’s lab at Princeton University found that mother worms who encounter pathogenic Pseudomonas aeruginosa in their environment learn to avoid the bacterium via a mechanism involving the retrotransposon Cer1. Cer1 is also needed for inheritance of avoidance behavior by the worms’ offspring, and its release into the environment can transfer avoidance behavior to naïve worms. Image courtesy of Murphy lab.