The genetics of smell

Research suggests that we all smell different smells thanks to our genes.

Research by scientists at Plant & Food Research, published this week in the journal Current Biology, has identified some of the genetic differences that determine an individual’s ability to smell various odours.

The researchers tested nearly 200 people for their sensitivity to ten different flavours that occur in food, then searched their genomes for areas of DNA that differed between those that could smell a given compound compared to those who could not. The study suggested that sensitivity to four of the compounds tested – isobutyraldehyde (malt), β-damascenone (apple), 2-heptanone (blue cheese) and β-ionone (violet flowers) – is based on genetic differences. The differences in sensitivity did not seem to be linked to ethnic background.

“We were surprised how many odors had genes associated with them,” says Jeremy McRae, one of the scientists involved in the study. “If this extends to other odours then we might expect everyone to have their own unique set of smells that they are sensitive to. These smells are found in foods and drinks that people encounter every day, such as tomatoes and apples. This might mean that when people sit down to eat a meal, they each experience it in their own personalised way.”

In the case of β-ionone, a smell closely associated with violets and present in foods such as tomatoes, oranges and Pinot noir wine, the research identified the exact change in the DNA sequence that relates to an individual’s sensitivity. Those who are sensitive to the smell describe it as a floral note, whereas others detect a pungent or sour odour.

“Knowing the compounds that people can sense in foods, as well as soaps, detergents and other goods, will have an influence on the development of future products,” says Plant & Food Research scientist Dr Richard Newcomb. “Companies may wish to design foods that better target people based on their sensitivity, essentially developing foods and other products personalised for their taste and smell.”