Quirks & Quarks

Do your genes smell bad? DNA shows what our noses know

Small differences in receptor genes may explain differences in our 'smellscapes'

Small differences in receptor genes may explain differences in our 'smellscapes'

New research may explain why one person's "smellscape" is significantly different from another's (PAUL ELLIS/AFP/Getty Images)
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Researchers have identified some fo the differences in our olfactory receptor genes may explain the large differences that can exists between individuals when it comes to the sense of smell.

Humans have 400 different types of odour detectors called olfactory receptors that sit at the top of our nose capturing scent information around us. The chemicals we breathe in activate a certain combination of these receptors, creating the perception of a specific smell.

The olfactory receptor's functionality is linked to an odor's perceived intensity. That may explain why some people are repulsed by the strong odor of aged cheese, while others are indifferent. (FABRICE COFFRINI/AFP/Getty Images)

"It's a complicated system because for vision, we only have three different types of photoreceptors that allow us to see every single colour," said Dr. Casey Trimmer, the lead author of the study, who's now a research scientist at the fragrance and flavour company Firmenich.

She wanted to understand how the receptors work together to help us perceive different smells, and organized an experiment in which researchers  asked 332 people to rate the intensity and pleasantness of close to 70 common odours that we encounter in our daily lives.

They also obtained DNA samples from all the participants to identify differences in olfactory receptor genes and how they affected odour perception. To their surprise, a change in a single receptor was enough to significantly affect a person's odour perception.

The same flower, two different reactions

"I think most people thought that because we have so many detectors, odours don't activate just one of those detectors, but multiple," said Trimmer.

"But that's not the case, and this makes us think that some of these genetic changes are reasons why people have such variations and liking for the things that they eat and drink."  

This means that when two people smell the same flower, one may detect a pleasant scent, while another might not smell anything.

They also found that the olfactory receptor's functionality is linked to an odour's perceived intensity. That may explain why some people are repulsed by the strong odour of aged cheese, while others are indifferent.