Sci. STKE, 2 October 2007
Sensory Perception What Awful Smell?
Elizabeth M. Adler
Science's STKE, AAAS, Washington, DC 20005, USA
Although a rose by any other name might smell as sweet, two people smelling it might not experience that "sweetness" the same way. Different people differ markedly in their perceptions of particular odors: For example, some people think the testosterone derivative androstenone smells pleasantly floral, others think it smells like sweat or urine, and others dont perceive its scent at all. Keller et al. expressed 335 putative human odorant receptors in a line of human cells that stably expresses accessory factors for odorant receptor expression and identified OR7D4--which is expressed in nasal epithelium--as encoding the receptor most responsive to androstenone. Searching a SNP database for OR7D4 polymorphisms and sequencing the OR7D4 coding region of 391 individuals enabled the identification of the most common OR7D4 allele and a variant with two amino acid substitutions (R88W and T133M, leading to their respective designation as RT and WM). OR7D4 RT responded to androstenone and the related androstadienone (but not to 64 other odorants), whereas OR7D4 WM failed to respond to any odorants (including androstenone and androstadienone). People who were heterozygous for RT and WM or homozygous for WM were in general less sensitive to these two compounds than people who were homozygous for RT--and tended to have more positive perceptions of these odors. Statistical analysis implicated genetic polymorphisms in OR7D4 in differences in androstenone and androstadienone perception, although they did not fully account for such differences, indicating that odorant receptor function per se contributes to the subjective perception of odor.
A. Keller, H. Zhuang, Q. Chi, L. B. Vosshall, H. Matsunami, Genetic variation in a human odorant receptor alters odour perception. Nature 449, 468-472 (2007). [PubMed]
Citation: E. M. Adler, What Awful Smell? Sci. STKE 2007, tw352 (2007).