Genetic variation in the ability to perceive and smell androstenone was first discovered in 2007. Androstenone is a possible sex hormone: when male pigs secrete it in their gonads, sows become sexual receptive. Humans also secrete it in their sweat and urine. Roughly 60% of people can perceive the chemical compound. Of the 40% who cannot perceive it, some can ‘learn’ to–how this happens is not clear. Of the people who can perceive, some find it pleasant and others not. A recent study in PLOS One by Lunde and colleagues has found that variation in the O7RD4 gene (linked to androstenone perception) results in varying hedonic responses to cooked meat. Driven by a potential ban in Europe on pig castration, the authors were interested in learning what response people might have to meat from non-castrated males. Increased amounts of androstenone in meat were rated less favorably by those with two copies of the wild type mutation (ability to smell androstenone) than those with the variant (and less sensitive to androstenone).
Variation in this gene within and among indigenous populations around the world might reveal some interesting cross-sections with cultural preferences for foods–this is research I am currently working on and hope to eventually expand to a broader-based cultural-linguistic-biological program of study in the field. While there are genomic data online for a limited number of populations (1000 Genomes and HapMap), these collections do not exploit the full gamut of variation in an evolutionary context as many are modern and admixed and/or the sample sizes are small. This is not to say that these projects aren’t tremendously valuable but they cannot capture existing variation within a population for specific research questions, such as OR7D4. Hopefully, we’ll one day have more known olfactory gene-ligand associations.