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 or five tab-separated columns, depending on the provider. Here is a representative, annotated example — synthetic rows, real format so you can see exactly what you are looking at — and what some famous rows actually mean.

Les mateixes dades en els dos formats

23andMe writes a single genotype column; AncestryDNA splits it into two alleles and writes 0 for a no-call. The rest of the file is identical, so recognising one shape means recognising both.

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.

Què és cada fila

rs4988235MCM6/LCTAG

Lactase persistence: the best-known variant for tolerating milk in adulthood.

rs1801133MTHFR--

A no-call: the chip could not read this position. Any file has tens of thousands of them, and they are not an error.

rs6025F5CT

Factor V Leiden, associated with higher thrombosis risk. Heterozygous here.

rs429358APOECT

The most-discussed APOE variant in consumer genetics. With rs7412 it defines the ε2/ε3/ε4 alleles.

rs7903146TCF7L2CT

The strongest common signal known for type 2 diabetes.

rs1815739ACTN3CC

The so-called "sprinter gene". CC means two non-functional copies of α-actinin-3.

Descarrega l’exemple

Complete text files, comment header included, to open in an editor or feed to a script. They are synthetic and say so on their first line.

Com fer servir aquest exemple

• ·Open it in a plain-text editor to see that the columns are separated by tabs, not spaces.
• ·Use it to test an analysis script before touching your real file, which is around 20 MB.
• ·Compare it with your own download: if the columns match, your file will work with any tool that accepts this format.
• ·Do not upload it here expecting a report — it is six positions, not the ~650,000 an analysis needs.

On descarregar el teu

Official instructions from each provider. You need the raw file, not the results PDF.

• 23andMe →
• AncestryDNA →
• MyHeritage →

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.