Markers / Gene
ALDH2
One position in this gene is readable from a home DNA test.
Alcohol flush reaction
rs671 · chr12:112,241,766 · G/A · evidence: established
Alcohol becomes acetaldehyde, which ALDH2 then clears. One change disables the enzyme so completely that a single working copy is not enough, and acetaldehyde builds up: flushing, nausea, racing heart.
| If you carry | What it means |
|---|---|
| No copies | No flush reaction expected |
| One copy | Flush reaction expected |
| Two copies | Strong flush reaction expected |
| Ancestry group | A (the effect version) | |
|---|---|---|
| African | 0.2% | |
| American | 0.3% | |
| East Asian | 17.4% | |
| European | 0.0% | |
| South Asian | 0.0% |
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.
Where this gene fits
If you have taken a home DNA test, these positions are already in your file.
Read my file