Genetics and individual ‘smellscapes’

From an article in the New York Times entitled You Will Never Smell My World the Way I Do:

The scent of lily of the valley cannot be easily bottled. For decades companies that make soap, lotions and perfumes have relied on a chemical called bourgeonal to imbue their products with the sweet smell of the little white flowers. A tiny drop can be extraordinarily intense.

If you can smell it at all, that is. For a small percentage of people, it fails to register as anything.

Similarly, the earthy compound 2-ethylfenchol, present in beets, is so powerful for some people that a small chunk of the root vegetable smells like a heap of dirt. For others, that same compound is as undetectable as the scent of bottled water.

These — and dozens of other differences in scent perception — are detailed in a new study, published this week in the journal PNAS. The work provides new evidence of how extraordinarily different one person’s “smellscape” may be from another’s. It’s not that some people are generally better smellers, like someone else may have better eyesight, it’s that any one person might experience certain scents more intensely than their peers…

The scientists who conducted the study looked for patterns in subjects’ genetic code that could explain these olfactory differences. They were surprised to find that a single genetic mutation was linked to differences in perception of the lily of the valley scent, beet’s earthiness, the intensity of whiskey’s smokiness along with dozens of other scents.

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14 thoughts on “Genetics and individual ‘smellscapes’

  1. I’m unusually sensitive to the smell of garlic, apparently.

    I remember attending a meeting with about seven or eight others. It was the height of the garlic season, and I commented on the strong garlicky scent in the air. (Gilroy, the “Garlic Capital of the World”, is about 35 miles south.) No one else could detect it.

    Fortunately, I love garlic.

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  2. I entered the first comment here. And then it disappeared. It definitely wasn’t guano worthy so I assume it was a glitch.

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  3. The article reminds me of a description in one of Oliver Sacks’ book of a guy who, due to heavy drug use, temporarily lost his capacity for abstract thinking but gained a capacity for making detailed drawings from memory. He also acquired a heightened, doglike sense of smell that he enjoyed immensely.

    Turns out the guy was Sacks himself, who like many med students was often hopped up on amphetamines in order to get through the long shifts as a resident.

    I’ll see if I can find the account and quote from it. It makes for great reading.

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  4. A popular demonstration often used in genetics class is showing the polymorphism in the ability to taste a chemical compound called PTC. For those capable of tasting it it has a bitter foul taste. Or so I am told .. I myself belong to the ~ 30% of people incapable of tasting it at all. The ability to taste is genetic, and depends mainly on sequence differences in a gene coding for a bitter taste receptor. The demonstration always was a bit hit in the classes I taught, as it is bizarre to learn that such large genetic differences in taste perception exist. For some people this even was a bit unsettling: I once did the demonstration in a group of parents of first-year students and one woman was very distraught by the fact that she was unable to taste the compound.

    For those of you who have worked under the tight regulations of a modern wetlab you may enjoy (and cringe at) reading how this property was discovered by A. L. Fox in 1931:

    Some time ago the author had occasion to prepare a quantity of phenyl thio carbamide, and while placing it in a bottle the dust flew around in the air. Another occupant of the laboratory, Dr. C. R. Noller complained about the bitter taste of the dust, but the author, who was much closer, observed no taste and so stated.

    If you think that was bad, it gets worse:

    He even tasted some of the crystals and assured Dr. Noller they were tasteless but Dr. Noller was equally certain that it was the dust he tasted. He tried some of the crystals and found them extremely bitter. With these two diverse observations as a starting point, a large number of people were investigated and it was established that this peculiarity was not connected with age, race or sex.

    Hey everybody, let’s all taste this unknown chemical stuff!

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  5. Joe Felsenstein: I heard that PTC has more recently been found to be carcinogenic, so these fun experiments are no longer done.

    A quick google search shows that PTC taste strips are still available commercially online, so I am guessing you can still taste it at very low harmless dosage. I haven’t examined its safety recently though, and since PTC is not completely harmless I can imagine that many teachers may want to avoid the risk altogether.

    Entropy: You should hear what some people working with microbes did to themselves.

    Yes, I recall the discovery of the role of Helicobacter pylori in causing ulcers involved a similar juicy story.

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  6. Since the whole investigation was about gebnetics and smells HOW surprised can they be to find a single gene doing the dirty deed?!
    if its true there is this gene it would mean everyone would smell things the same.
    I say we never smelled anything in our lives. We only observe ‘smells’ in our memory. just as right now you could IMAGINE any smell you want. this because smells are in our memory. yet when we received the scent through our nose it only aLSO goes onto our memory screen. its just a recent one and so fast one would be decieived that one is actually smelling something.
    I think thats , lIKELY, what surprises them.
    Any gene difference is only changing the memory and not the ability to smell or the scent.
    Yet all smells out there are real. not made up in our heads as some researchers say.
    i’m suspicious of all these gene claims they make YET it does work to show smells are of one kind. Then error due to editting in the memory or some gap.

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  7. I can’t taste PTC. I also have virtually no food dislikes. My kids insist it’s ‘cos I can’t taste anything!

    Coriander’s another one that divides. I love it, but some friends can’t abide it. Again, the difference is genetic.

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  8. Allan Miller:
    I can’t taste PTC. I also have virtually no food dislikes. My kids insist it’s ‘cos I can’t taste anything!

    Coriander’s another one that divides. I love it, but some friends can’t abide it. Again, the difference is genetic.

    I don’t understand this. If we dislike something for years and then later come to like it, how can it be genetic?

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  9. walto: I don’t understand this. If we dislike something for years and then later come to like it, how can it be genetic?

    Well, it is! That is, there is a genetic predictor of whether one will or will not like it. But things do change, and the correlation is not 100%. The 2018 Royal Institution Christmas Lectures (a tradition since 1825, aimed at inspiring kids) showed a blind genetic test, among which was the prediction that the subject would be a cilantrophobe. She wasn’t, illustrating the dangers of a naive genetic determinism, 1 gene per trait, on or off.

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  10. In the early 20th century, after the rediscovery of Mendel’s work, it took forever for geneticists to understand that there wasn’t one gene for the nose, one for the ear, one for the thumb, etc.

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  11. walto: I don’t understand this. If we dislike something for years and then later come to like it, how can it be genetic?

    Why do kids hate mushrooms? It seems to me that many food aversions turn on at just about the time when kids are old enough to wander away fro their foraging parents.

    And there are many foods that we hated as kids but learn to like.

    At the risk of adaptationism, I think there is a safety related issue in being being picky in childhood and being able to learn to like culturally tested foods.

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