Why do taste and smell differ among individuals? 20/8/03. By the Weizmann Institute Some genes for the nose's odour-detecting receptors found to be 'optional'.

"De gustibus non est disputandum" is a popular saying, conveying that one shouldn't argue about flavours. Now, a team at the Weizmann Institute of Science in Israel, headed by Professor Doron Lancet, has found why this is true.

In our genome, around 1000 genes code for the nose's odour-detecting receptors (responsible for our sense of smell and a great part of flavour perception). Of these, more than half have become totally inactive in all humans, a fact that has been known for years.

Now a surprising discovery, published in Nature Genetics, shows that at least 50 genes are 'optional' – they can be active in some individuals and inactive in others. This high level of genetic variation among individuals is most unusual.

A simple calculation, based on the new findings, shows that nearly every human being would display a different pattern of active/inactive receptors – an individualised genetic barcode. The uncovered genetic heterogeneity affects the way thousands of aromas and flavours are perceived. Furthermore, the new research shows that the level of obliteration of olfactory receptors varies among different ethnic groups.

The novel discovery has profound implications for the way the perfume, food and beverage industries handle the discovery of new aroma, flavour and fragrance ingredients. Usually one person, or a small test panel, makes sensory decisions taken to represent billions of customers. But since every nose is different, industry might rethink such issues.

The investigators believe that soon a DNA chip could be used to perform olfactory genetics typing of panels and target audiences alike. Thus, cosmetics and foodstuff design would be revolutionised in much the same way that the drug industry now seriously contemplates developing tailor-made medications based on the breakthroughs of pharmacogenetics.

Adapted from a press release by the Weizmann Institute.