Genes

Several years ago the internet was captivated by the enigma of “the dress specifically, was the dress black and blue, or was it white and gold? No matter what you saw, the viral debate serve to highlight that humans differ remarkably in how they each perceive our personal sensory world.
By showing that small changes in a single olfactory receptor gene can affect; so how strong and pleasant a person finds an odor, the findings expand understanding of how olfactory receptors in the nose encode information about the properties of odors even before that information reaches the brain.

Specialize sensor proteins

Humans have about 400 different types of specialize sensor proteins; hence know as olfactory receptors, in their noses. One odor molecule can activate several different olfactory receptors; so while any give receptor can activate by several different odor molecules. The olfactory system some how interprets these receptor activation patterns to recognize the presence and intensity of millions, maybe even trillions, of different smells.

Small differences in olfactory receptor genes; which are extremely common in humans; so can affect the way each receptor functions. These genetic differences mean that when two people smell the same molecule; so one person may detect a floral odor while another smells nothing at all.

In the current study, publish online in advance of print in the Proceedings of the National Academy of Sciences; so the researchers examine this phenomenon on a large scale by asking 332 people to rate the perceive intensity (strength) and pleasantness of nearly 70 odors. Many of the odors use are common components of food flavor; so providing real-world relevance to the study.

The obtained DNA samples

The scientists also obtain DNA samples from the subjects and use high throughput sequencing technology to identify differences in the DNA of over 400 olfactory receptor genes from each subject. Finally, using sophisticate mathematical models, they ask if and how differences in each gene affect odor perception.
They use people’s genes to identify who has a broke form of a given receptor and compare their odor perception to that of individuals having the more functional version of that receptor. The results were surprising: A change in a single receptor was often sufficient to affect a person’s odor perception.
Because most odors activate several receptors; so many scientists thought that losing one receptor wouldn’t make a difference in how they perceive that odor. Instead, our work shows that is not the case and changes to a single receptor can make a big difference in how you perceive an odor,” said Mainland.
For example, people with a less functional version of an olfactory receptor; hence know as OR11A1 found the odor molecule 2-ethylfenchol to be less intense; so than did individuals with a better-functioning version of this receptor. Moving forward, the researchers will seek to broaden their understanding of the olfactory system; hence by using more sophisticate mathematical models to examine the contribution of multiple receptors to odor perception.