Human Olfaction

Previous studies examining human olfactory variation have found high variability in olfactory receptor (OR) genes between individuals, sexes, and within and between populations. Humans are also incredibly variable in their phenotypic perception of odors. The full extent of OR genotypic variation and its evolutionary underpinning leading to the diversity of modern phenotypes is unknown. Some research has suggested that evolutionary differential adaptation plays a role in variation within the olfactory subgenome, including weakly expressed pseudogenes. My research is organized around testing the hypothesis that human OR genetic variation is the result of adaptation to local and novel environments (cultural and biological) and has resulted in complex modern olfactory phenotypes and genetic diversity within and between populations.

My current objective is to establish the extent of ecological variation in the evolution of human olfaction. Specifically, I am interested in the mechanisms (drift and selection) giving rise to human genotypes and subsequent complex phenotypes. We hypothesize that patterns of OR gene variation between diverse human populations are linked to biological and cultural adaptation to novel environments. Unique to humans, this biocultural evolution incorporates both cultural and ecological factors into models of gene frequency change between generations.

Grant Sponsorship
2015          PI: Paleogenomic reconstruction and functional testing of archaic hominin olfactory receptors. National Science Foundation grant BCS-1550409. $47,857

Relevant Publications
2015. Hoover KC, Gokcumen O, Qureshy Z, Brugeura E, Savangsuksa A, Cobb M, Matsunami H. Global survey of variation in a human olfactory receptor gene reveals signatures of non-neutral evolution. Chemical Senses 40(7):481-488. DOI: http://10.1093/chemse/bjv030 (5 Year Impact Factor: 2.886). Altmetric score 125 (top 5% of research output).

2013. Hoover KC. Evolution of olfactory receptor cells and genes. In: J Walker, Ed: Olfactory Receptors: Methods and Protocols. Methods in Molecular Biology Series. New Jersey: Humana Press

2011. Hoover KC. The scent emotion, sex, and evolution. Invited editorial. Maturitas 70:1-2.

2011. Hoover KC. Smell with inspiration…the evolutionary significance of olfaction. Yearbook of Physical Anthropology 143(51):63-74. Impact Factor 1.286. DOI: 10.1002/ajpa.21441. #11 in the AJPA (includes Yearbook) Top Downloaded Articles in 2011.

2009. Hoover KC. The Geography of Smell. Cartographica: The International Journal for Geographic Information and Geovisualization 40: 237–239. DOI: 10.3138/carto.44.4.237

Media

5 responses to “Human Olfaction

  1. Mark currie

    Appreciate your work. Any info on response to smell of fire/smoke, specifically distinguishing humans from chimps, etc, and when difference appeared

  2. Most mammals will run from fire and are alert to smoke as a sign of fire. There is a gene that is linked to the smell of smoke but no evidence to suggest we are different in our perception of it. Our response to it likely has a cultural element–in the sense that we use context to determine if it is a good smell (BBQ smoke, controlled burns) or a dangerous smell (wild fires).

  3. Markstuartcurrie

    Thanks so much for your reply. Would be fascinating to find a difference, eg do we desensitize more quickly? Kind of interesting that odor of smoke typically will not wake a sleeping human. Are our ape cousins different there? I believe our exploitation of fire may go back perhaps almost as far as bipedalism, and finding a genetic time stamp would be huge.

  4. You are right–use of fire is actually younger than bipedalism, which emerged about 6-8 million years ago (depending on the species you look at). Use of fire within the genus Homo dates to about 1.7 million years ago and Homo erectus–Neandertals also used fire. Good question as to whether apes will wake if they smell smoke–maybe they would (animals certainly have strong behavioral responses to fire) but we don’t b/c we can control it…? The problem is that even if we have a putative link between an olfactory receptor gene and a ‘smokey’ smell, we do not know if that is the only gene that controls smell reception of smokey things. Also, that gene is present in apes so it and any variation in it may not be biologically meaningful… In other words, I suspect that the awareness of fire via a smokey smell and its danger/safety is probably linked more to cultural practices and knowledge than it is to a genetic cause!

  5. Markstuartcurrie

    Perhaps a more testable question relevant to your field would be response to odorants specific to cooked food. Humans certainly seem very sensitive to smoked/burned fat like bacon and barbecue as you mentioned. Would be interesting to look at upsteam regulation of some of those odorant receptors to see if expression increased dramatically in some era. i.e. Maybe there is a genetic time stamp for cooking in OR regulation or response genes in archaic hominids? (I know the technologies for looking at ancient DNA is just beginning to reach that far back, but the ape human comparison still might reveal where to look)

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