Gene Differences Affect How People Smell Things, New Study Finds

A new study suggests that variations in people’s genes may cause them to smell things differently. Scientists have long known that people perceive odors differently, but it is unclear why and how this occurs. To gain deeper insight on the human sense of smell, researchers asked around 300 participants to smell 150 different odors. Then, the participants were instructed to rate the intensity and pleasantness of each smell. They also had to provide blood samples for the researchers to analyze. After looking at each participant’s DNA and odor ratings, the researchers found that a small difference in genetic makeup causes the differences in people’s perception of odors. According to the researchers, the human nose has around 400 smell receptors, which allow us to detect different scents. Different odors activate certain combinations of receptors. These receptors pass information to the brain, which then dictates the intensity and pleasantness of an odor. Therefore, if there are differences in these receptors due to genetic variations, two people will not perceive a single odor in the same way. The researchers consider their findings a breakthrough in understanding the sense of smell. Doctor Joel Mainland said that these findings disprove the theory that changes in one receptor would not make a difference in smell perception. He emphasized that changes to one receptor can really alter the way a person can smell a scent. However, an expert who is not involved in the study pointed out that other factors, including previous experiences associated with the scent, could also influence a person’s sense of smell.