Abstract
In studies of vision and audition, stimuli can be chosen to span the visible or audible spectrum; in olfaction, the axes and boundaries defining the analogous odorous space are unknown. Features governing the physical transport of molecules to olfactory receptors are sufficient to reliably classify novel molecules as odorous or odorless (AUROC = 0.97). Applying this model to a database of all possible small organic molecules, we estimate that over 30 billion possible compounds are odorous, 6 orders of magnitude larger than current estimates of 10,000. Remarkably, nearly all transport-capable molecules are odorous, suggesting broad collective tuning of olfactory receptors. Defining the boundaries of odor perception will enable design of experiments that representatively sample olfactory space and efficient search for novel odor compounds.
Competing Interest Statement
J.D.M. received research funding from Ajinomoto Co., Inc.
