The striped zebrafish is a popular pet, not uncommon in aquariums. But it may have a lot more in common with pet owners than you might guess by looking at it—humans actually share 70 percent of our genes with the little swimmers. This is cool for many reasons; for one, the zebrafish can repair its own heart, and the commonalities have made it a focus of medical research. And now, in this week’s Proceedings of the National Academy of Sciences, researchers have identified the receptor for the particularly putrid aroma of cadaverine, also known as rotting flesh.
Cadaverine or putrescine (a related compound that is also caused by decomposing organisms) is a positive signal for many species. For rats or goldfish, the smell could mean there’s food nearby; for certain insects, it could point to a good place to lay eggs. For some felines, it’s a social cue that they use to mark territory, and for yet other species, it can be a sign of danger. As it turns out, zebrafish—like humans—are averse to the smell produced by rotting dead things.
“It signals danger, if a dead body is lying around maybe the danger is still around. It could also signal that the meat is toxic and should not be eaten,” study author Sigrun Korsching told BBC News.
Cadaverine is produced during the decomposition process of animal tissue and sometimes is also produced by living beings. When the odor reaches the receptor in zebrafish, it travels to the brain and triggers evasive behavior.
While this study focused on the zebrafish receptor—identified as TAAR13c—there could be implications for a similar neural network in humans.