Continuously updated · 7 variants · last reviewed Sep 5, 2026
Nearly everything else on this site is a probability. A variant nudges the odds of a condition, or the dose of a drug, and you could never tell from the inside which way your own copy fell. Smell and taste are the exception: the variant does not shift a risk, it changes the perception itself. One person smells the asparagus. The person next to them does not. Both are right about what they experienced.
This is also where the rest of the site connects. What tastes bitter decides what gets eaten, what gets eaten shapes the diet, and diet sits upstream of a good number of the conditions we cover. Losing smell can be an early sign in neurological disease. Flavour is not a curiosity bolted onto a genetics reference — it is where the genome meets food.
What reaches you, and what does not
Humans carry around 400 working odorant receptor genes, and they are among the most variable genes we have — two people can differ at a receptor so completely that one of them is blind to a smell the other finds obvious. These are the best-studied of those differences.
OR2M7 · rs4481887
Read the genotypes → StandardTAAR5 · rs41286168
Read the genotypes → StandardUGT2A1 / UGT2A2 · rs7688383
Read the genotypes → StandardABCC11 · rs17822931
Read the genotypes →Written up in full: Smell Perception and Specific Anosmias
Why the same food is not the same food
Taste receptors sit on the tongue and read molecules directly, so a change in the receptor is a change in the flavour. The bitter receptor TAS2R38 is the classic case: three coding changes travel together, and which pair you inherit decides whether a whole family of vegetables tastes bitter or tastes of almost nothing.
TAS2R38 · rs713598
Read the genotypes → StandardTAS2R38 · rs1726866
Read the genotypes → StandardTAS2R38 · rs10246939
Read the genotypes →Written up in full: Bitter Taste Perception (TAS2R38)
Vanillin
C8H8O3
The aromatic ring your olfactory receptors read as vanilla.
Phenylthiocarbamide (PTC)
C7H8N2S
The bitter molecule TAS2R38 binds — the compound the classic taster test is run with.
Both are aromatic — a ring with a particular set of groups hung off it. A receptor reads that shape, and a coding change in the receptor changes what the shape is read as. That is the whole mechanism, and it is why a single base can decide what a food tastes like.
A position in your genome does not mean one thing. The same variant reaches out to the condition it is linked to, the way a medicine moves through you, and what you can smell and taste — and we publish all three sides of it.