Markers / Gene
CHRNA5
One position in this gene is readable from a home DNA test.
How hard nicotine grips, if you smoke
rs16969968 · chr15:78,882,925 · G/A · evidence: established
This change alters a nicotine receptor subunit in the brain. It does not make anyone start smoking, but among people who do smoke it is one of the strongest known predictors of how many cigarettes a day they end up on and how hard quitting is.
| If you carry | What it means |
|---|---|
| No copies | You do not carry it, so nicotine has no extra grip from this gene |
| One copy | One copy, a somewhat harder time quitting if you smoke |
| Two copies | Two copies, a markedly harder time quitting if you smoke |
| Ancestry group | A (the effect version) | |
|---|---|---|
| African | 2.3% | |
| American | 20.9% | |
| East Asian | 2.7% | |
| European | 36.6% | |
| South Asian | 18.2% |
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.
Where this gene fits
If you have taken a home DNA test, these positions are already in your file.
Read my file