Markers / Gene
FTO
One position in this gene is readable from a home DNA test.
FTO, the body weight variant
rs1421085 · chr16:53,800,954 · T/C · evidence: established
The best-known common variant affecting body weight. This particular position is the one shown experimentally to be the cause rather than merely a marker: it disrupts a control site so that developing fat cells switch towards storing energy instead of burning it.
| If you carry | What it means |
|---|---|
| No copies | You have the lower-weight version on both copies |
| One copy | One higher-weight copy, about a pound and a half on average |
| Two copies | Two higher-weight copies, about three pounds on average |
| Ancestry group | C (the effect version) | |
|---|---|---|
| African | 5.6% | |
| American | 23.9% | |
| East Asian | 16.9% | |
| European | 43.2% | |
| South Asian | 30.7% |
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