23andMe Raw Data Example: What a Raw DNA File Looks Like
A 23andMe (or AncestryDNA / MyHeritage) raw data file is plain text: one row per genetic position, four tab-separated columns. Here is a real, annotated example so you can see exactly what you are looking at — and what some famous rows actually mean.
An annotated example
The first line is the header; each following line is one measured position. Real files have ~650,000 rows.
| rsid | chromosome | position | genotype |
| rs4988235 | 2 | 136608646 | AG |
| rs6025 | 1 | 169519049 | TT |
| rs429358 | 19 | 45411941 | CT |
| rs1815739 | 11 | 66328095 | CC |
- rsid
- — the variant's reference ID in dbSNP (e.g. rs429358)
- chromosome
- — 1–22, plus X, Y, MT
- position
- — base-pair coordinate (build GRCh37/hg19)
- genotype
- — the two letters you carry, one from each parent
Positions use genome build GRCh37 (hg19); a genotype of -- (or 0) means the chip could not read that position.
What those example variants mean
Every rsid links to its dbSNP entry. This is a starting point, not a diagnosis — single variants rarely determine an outcome.
| rsID | Gene | Associated with |
|---|---|---|
| rs4988235 | LCT | lactose tolerance in adulthood |
| rs6025 | F5 | Factor V Leiden — blood-clotting risk |
| rs429358 | APOE | with rs7412, the strongest common Alzheimer's risk factor |
| rs1815739 | ACTN3 | the "sprint gene" — muscle fibre type |
| rs9939609 | FTO | body-weight / obesity association |
| rs1801133 | MTHFR | folate metabolism (often over-interpreted) |
Want yours read automatically?
Upload your own raw file and we cross-reference all ~650,000 positions against the GWAS Catalog, PharmGKB and ClinVar — free.
Read the full guide: how to interpret your 23andMe raw data →