The sense of smell plays an important role in issues related to quality of life (e.g., appreciation of food and drink, fine fragrances, gardens and other wildlife, and perhaps the odor of other people). Smells also warn of danger (e.g., the odor of warning agents in natural gas, that of spoiled foods, or, in the workplace, signs that a process or environment might require attention). To appeciate odors individuals must have a fully functional olfactory system - the primary receptors for odorants, which are constructed from genes that encode specific proteins, are the filters through which humans experience the reality of their odor environment. If these filters provide information that differs across individuals, then reality is not the same for everyone. Previous research has shown that people do differ in their perception of odors: Some people cannot smell the odors of single compounds. This is termed specific anosmia and can be measured as an absence in perception when an odorant is present or as a shift in sensitivity to the odorant such that the person is much less sensitive to it or its perceived intensity is diminished. In other situations an odor may be smelted, but its impact may be different across individuals (e.g., the odor of the herb cilanro is quite pleasant for some people while others find the smell offensive). At present, the biomedical community does not fully understand how the sense of smell works; however, understanding the biological bases of differences across people can provide a significant advance to this end. In this project, we will study olfactory perception in approximately 1,600 African Americans, Asians, Caucasians and Hispanics who also will donate samples of their DMA. The goal is to correlate variation in sensitivity and responses to odors with known underlying variation in genes that are thought to be responsible for building the initial filters (proteins) that are expressed on the olfactory receptor cells in the nose. To do this, we will assess individual behavioral responses to odors and characterize the genes for olfactory receptors that are found within the person's genome.
