[Genetic determination of smell]

The recent study of olfactory receptor genes sheds new light on the significance of this receptor not only for smell recognition but also in human embryogenesis. In this work current data concerning the role of olfactory receptors in human as well as their genetic determination are presented. Olfactory receptors are encoding approximately by 1000 hOR genes. The hOR gene family is most likely the largest in human genome. Among 1000 hOR genes, 347 are functional, the rest 70% being pseudogenes are not expressed. HOR genes reside at 25 locations in human genome in multiple clusters on all human chromosomes, except 2, 4, 18, 20, 21, and Y. Each receptor recognizes single as well as multiple odorant, and each odorant binds to multiple receptors to generate specific activation patterns for each of a great number of distinct smells. There is more and more evidence showing close correlation between HLA complex and smell recognition, which influence mating behavior in animals, consequently leading to increase immune response to various pathogens. The last investigations showed hOR expression in germinal cells and in developing embryo, suggest that hOR may play functional role in cell recognition in organogenesis.