Taste by touch in octopus

Sensory receptors are at the interface between an organism and its environment and thus represent key sites for biological innovation. Octopuses are a rich source for biological novelty: they exhibit complex cognition and behavior similar to vertebrates but via entirely distinct organization and evolutionary history. Indeed, among the most unique octopus traits is a complex distributed nervous system that enables autonomous, chemosensory arm behavior. Our lab recently discovered a novel family of chemotactile receptors (CRs) that mediate “taste by touch” arm exploration. CRs diverged from neurotransmitter receptors to form pentameric ionotropic receptors that detect poorly soluble molecules for contact-dependent chemosensation. Here, I will describe our curiosity-based exploration of octopus “taste by touch” as a striking example of evolution that can be leveraged to understand the molecular basis of novelty across levels of biological organization.