Scientists Create the First Map of Smell Receptors in the Nose
Smell has long seemed random, but new research reveals the nose is meticulously organized. Scientists found that each of the roughly 1,100 odor receptors is expressed at a precise position from top to bottom in the nasal lining. A chemical gradient of retinoic acid, a form of vitamin A, acts like a positional guide, switching on specific genes that tell immature smell cells which receptor to become. This spatial code ensures that the sensory map in the nose aligns precisely with the corresponding map in the brain's olfactory bulb. The discovery solves an old puzzle about how the olfactory system keeps its vast array of smell channels orderly, and it could reshape our understanding of how the brain processes scents.
Dorsoventral epithelial position induces graded expression of a transcriptional program that maps each of the 1,100 olfactory sensory neuron
