Genetic variation across the human olfactory receptor repertoire alters odor perception.

Humans use a family of more than 400 olfactory receptors (ORs) to detect odors, but there is currently no model that can predict olfactory perception from receptor activity patterns. Genetic variation in human ORs is abundant and alters receptor function, allowing us to examine the relationship between receptor function and perception. We sequenced the OR repertoire in 332 individuals and examined how genetic variation affected 276 olfactory phenotypes, including the perceived intensity and pleasantness of 68 odorants at two concentrations, detection thresholds of three odorants, and general olfactory acuity. Genetic variation in a single OR was frequently associated with changes in odorant perception, and we validated 10 cases in which in vitro OR function correlated with in vivo odorant perception using a functional assay. In 8 of these 10 cases, reduced receptor function was associated with reduced intensity perception. In addition, we used participant genotypes to quantify genetic ancestry and found that, in combination with single OR genotype, age, and gender, we can explain between 10% and 20% of the perceptual variation in 15 olfactory phenotypes, highlighting the importance of single OR genotype, ancestry, and demographic factors in the variation of olfactory perception.

Sex-steroid derived compounds induce sex-specific effects on autonomic nervous system function in humans.

The physiological and psychological effects of 2 human sex-steroid derived compounds, 4.16-androstadien-3-one (AND) and l,3,5(10),16-estratetraen-3-ol(EST) were measured in 24 subjects who participated in a within-subjects, double-blind experiment. A dissociation was evident in the physiological effects of AND, in that it increased physiological arousal in women but decreased it in men. EST did not significantly affect physiological arousal in women or men. Neither compound significantly affected mood. AND is an androgen derivative that is the most prevalent androstene in human male sweat, male axillary hair, and on the male axillary skin surface. The authors argue that AND's opposite effects on physiology in men and women further implicate this compound in chemical communication between humans.