According to a couple of studies that were published in the journal Current Biology on the 1st of August, researchers have managed to discover the genetic differences that are responsible for the differences in smell perspective and sensitivity among various individuals. Approximately 200 subjects took part in the study, led by a research team from the Plant and Food Research center in New Zealand. Each subject was tested for 10 different chemical compounds that are most commonly found in ever day food. After testing the sensitivity of the subjects for the chemical compounds, the research team investigated their genome in order to discover the genetic differences between subjects who could smell certain chemicals, and subjects who couldn’t smell the chemicals.
The research team, composed of Jeremy McRae, Sara Jaeger, and Richard Newcomb, revealed genetic associations for 4 of the 10 studied chemicals. Their findings suggest that our different genetic make-up determines whether or not a certain individual can sense the smell of certain chemicals. The four odorants found to be genetically associated are those of apple, ionone, malt and blue cheese.
Jeremy McRae, one of the authors, reports that there was a certain surprise for the team when they discovered that so many odors are associated with certain genes. If their future studies reveal other odors to be associated with genes, the results would mean that each individual is sensitive to a certain palette of smells. According to McRae, the results of their current studies show that each individual has a personalized experience with the smell of their food, each time he or she sits down to eat.
McRae and his research colleagues also compared the differences between human subjects found in various parts of the world. However, they found no evidence of regional differentiation. This results means that, for example, an individual who lives in Asia is most likely to be able to smell the same chemical compounds as an individual from Africa, Europe or America. Furthermore, there is no noticeable relationship between the ability to smell different chemical compounds. Basically, if a subject is sensitive to the smell of blue cheese, it doesn’t mean that he or she has to be sensitive to the smell of malt or apple.
The research team discovered that there are various genetic variants that are linked to the encoding of the human olfactory receptors. These olfactory receptor molecules are found on the surface of each sensory nervous cell from the human nose. When a chemical compound is bound to the olfactory receptor, an electrical impulse is sent from the nervous cell towards the brain. This electrical impulse is responsible for our smell perception.
In the case of ionone, which is the chemical compound that gives the smell of the flowers known as violets, the research team discovered the exact genetic mutation that causes certain individuals to perceive the smell as floral, rather than sour. Their perception is related to the mutation of the OR5A1 gene. According to Richard Newcomb, the current study allows the development of future products aimed for the human population. Companies might use the results of the study to create better smelling foods or beverages, based on the smell sensitivity of their target population.