Genes Determine Why We Don’t All Smell the Same

MedicalResearch.com Interview with:

Dr. Casey Trimmer, PhDGeneticist, was a post-doctoral fellow at the Monell Center when the research was conducted

Dr. Trimmer

Dr. Casey Trimmer, PhD
Geneticist, was a post-doctoral fellow at the
Monell Center when the research was conducted

MedicalResearch.com: What is the background for this study?  

Response: We detect odors using 400 different types of sensor proteins, called olfactory receptors, in our noses. An odor molecule activates a specific combination of these receptors, and this pattern of activation gives us information on what we’re smelling–whether its floral or smoky, intense or weak, and how much we like it. However, how the system translates receptor activation to these perceptual features is largely unknown. Here, we take advantage of the extensive genetic variation in the OR gene family to understand the contribution of individual ORs to odor perception. By studying cases where the function of a particular OR is lost, we can examine what kinds of perceptual alterations occur, allowing us to link receptor to odor and understand what kind of information the receptor is encoding.

Data linking genetic variation to perceptual changes exist for only 5 ORs. Here, we examined the perceived intensity and pleasantness of 68 odors in 332 participants. We used next-generation genome sequencing to identify variants in 418 OR genes and conducted a genetic association analysis to relate this variation to differences in odor perception. We then use a cell-based assay to examine receptor function and investigate the mechanisms underlying our associations. Finally, we examined the contribution of single OR genotype, genetic ancestry, age, and gender to variations in odor perception.

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Who Suffers From Phantom Smells?

MedicalResearch.com Interview with:
“Bad smell” by Brian Fitzgerald is licensed under CC BY 2.0Kathleen Bainbridge, PhD

Epidemiology and Biostatistics Program
NIDCD

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The causes of phantom odor perception are not understood. This study looked for the prevalence and risk factors for this disorder. We found that that 1 in 15 Americans (or 6.5 percent) over the age of 40 experiences phantom odors.

This study, is the first in the U.S. to use nationally representative data to examine the prevalence of and risk factors for phantom odor perception. The study included about 7,400 adults who participated in the National Health and Nutrition Examination Survey, a continuous survey conducted by the National Center for Health Statistics which is part of the Centers for Disease Control and Prevention. The study could inform future research aiming to unlock the mysteries of phantom odors.

We identified risk factors that may be related to the perception of phantom odors. People are more likely to experience this condition if they are female, and are relatively young—we found a higher prevalence in 40-60 year-olds compared to 60+ year-olds. Other risk factors include head injury, dry mouth, poor overall health, and low socio-economic status. People with lower socio-economic status may have health conditions that contribute to phantom odors, either directly or because of medications needed to treat their health conditions.

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Your Genes May Explain Mosquitoes’ Preference For Your Odor

G. Mandela Fernández-Grandon PhDNatural Resources Institute,University of Greenwich,Chatham, United KingdomMedicalResearch.com Interview with:
G. Mandela Fernández-Grandon PhD
Natural Resources Institute,
University of Greenwich,
Chatham, United Kingdom

Medical Research: What is the background for this study?

Response: People often wonder why, when they are out with their friends or family, one person seems to get ravaged by mosquitoes but others come away relatively bite free. Mosquito bites can be a nuisance to many of us but they are no trivial matter. Mosquitoes are one of the most serious threats to public health through the transmission of diseases such as malaria, dengue fever, yellow fever, chikungunya and others.

We knew that mosquitoes rely on odour to find their hosts but until now the link between our body odour and genes had only been shown using human sniffers1. In a strictly controlled laboratory environment, we were able to present the odours of individuals in identical and non-identical twin pairs to mosquitoes allowing them following the odour stream of whichever they found to be more attractive.

Medical Research: What are the main findings?

Response: Mosquitoes are equally attracted to identical twins in a pair but with non-identical twins they display a preference for one individual.

The ability of mosquitoes to distinguish non-identical twins but not identical twins suggests a genetic basis for our odour profile, a genetic difference which plays a role in whether we get bitten more or less than others.

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