rs4481887
Smelling asparagus in urine
What this position does
Almost everyone produces the sulphur compounds after eating asparagus. Only some people can smell them, and this position sits in a cluster of smell-receptor genes.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version GG | Less likely to detect it Neither copy carries the detection-associated version. |
| One copy AG | More likely to detect it One copy of the detection-associated version. |
| Two copies AA | Most likely to detect it Two copies of the detection-associated version. |
Worth knowing. This is about the nose, not the urine. Nearly everyone produces the compounds.
How common each version is
| Ancestry group | A (the effect version) | |
|---|---|---|
| African | 10.0% | |
| American | 21.8% | |
| East Asian | 13.8% | |
| European | 27.7% | |
| South Asian | 10.2% |
1000 Genomes Project phase 3, via Ensembl, retrieved 2026-09-23. These groupings are coarse and flatten a great deal of internal diversity, particularly within Africa. A variant being common somewhere tells you where a piece of your ancestry probably comes from, and nothing else.
How many people carry each result
| Ancestry group | GG | AG | AA |
|---|---|---|---|
| African | 537 / 661 | 116 / 661 | 8 / 661 |
| European | 264 / 503 | 199 / 503 | 40 / 503 |
| East Asian | 377 / 504 | 115 / 504 | 12 / 504 |
| South Asian | 392 / 489 | 94 / 489 | 3 / 489 |
| American | 216 / 347 | 111 / 347 | 20 / 347 |
Counts of people, not modelled frequencies: every one of the 2,504 individuals sequenced by the 1000 Genomes Project phase 3, tallied by the genotype they carry. Deriving these from allele frequencies instead would assume random mating inside each group and undercount the homozygotes.
How to find out which you have
If you have taken a test with 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, TellMeGen or Living DNA, this position is very likely already in the raw data file they gave you. You do not need another test.
One thing to watch if you look it up by hand: testing companies report some positions from one DNA strand and some from the other, and the file does not say which. Read the letters as they appear and you will get the opposite of the truth for some positions. Sequencings resolves that automatically.
Source
Coordinates and allele pair verified against Ensembl GRCh37. Direction of effect verified against VEP protein consequences or 1000 Genomes population frequency. Category: Trait.
Where this fits
Common questions
What is rs4481887?
rs4481887 is a position in the near OR2M7 gene on chromosome 1. Almost everyone produces the sulphur compounds after eating asparagus. Only some people can smell them, and this position sits in a cluster of smell-receptor genes.
What does it mean if I have AA at rs4481887?
Most likely to detect it. Two copies of the detection-associated version.
What does it mean if I have GG at rs4481887?
Less likely to detect it. Neither copy carries the detection-associated version.
How do I find out my rs4481887 genotype?
If you have taken a home DNA test, this position is very likely in the raw data file you were given. Sequencings reads that file in your browser without uploading it, and resolves which DNA strand each position was reported from, which is the step most manual lookups get wrong.
This is reference information, not medical advice, and not a diagnosis. See the medical disclaimer. Category: Trait.