© 2004 AAAS
In A, a 40-day-old mouse in which one nostril was cauterized at birth shows a single X-gal stained M71 glomerulus at the half bulb corresponding with the open nostril (bulbO). In B, two glomeruli appear in the half bulb corresponding to the closed nostril (bulbX) – a seeming sign of immaturity. In the graphs C and D, the critical period for glomerulus maturation appears longer for M71 than for the closely related odorant receptor M72.
A smell can conjure intimate memories and even change behaviors. Scent is primal, so closely related to territoriality, predation, food, and sex in many animals, yet to most humans it seems an accessory, like a dab of perfume. People devote much more conscious attention to vision and taste, which have three and five receptor types, respectively. The human genome, however, has 350 intact odorant receptor genes, and other mammals have many times ...
