Why is a SNP missing from your results?
If DNAHelper shows that a marker is missing it is almost always about your file — not an error. Here is the honest explanation.
Providers measure different parts of your DNA
Your raw data file does not contain your whole genome — it contains the ~600,000–700,000 positions that your specific provider's test chip measures. MyHeritage, 23andMe, AncestryDNA and FamilyTreeDNA use different chips with different SNP sets. A position present in a 23andMe export can be entirely absent from an AncestryDNA export.
Why we show "missing" instead of guessing
When a research link is built on an rsID your file does not contain, we cannot read your genotype there. The alternatives are hoping that imputation (statistical guessing of missing positions) happens to land right — or telling the truth. DNAHelper chooses the truth: the marker is shown as missing and the result marked accordingly. A guessed genotype that happens to be wrong is worse than no answer.
It does not affect the rest of your results
Missing markers are selective — every position that is in your file is analyzed normally with full evidence grading. What you see is what your file can actually answer.
What you can do
- Tested with several providers? Try another export — the chips differ, so another file may contain the marker.
- Check our format comparison: file formats by provider shows what each export contains.
- Unsure if something is wrong? See the support page — but remember we never ask you to email your DNA file.
Technical: imputation and reference builds
Some services use imputation to fill gaps — statistical estimation of missing genotypes from reference panels. It can be useful for research but adds an uncertainty layer DNAHelper deliberately avoids in the consumer view. Read what imputation is and how we assess evidence in the methodology.
Also: What is a SNP? · What is imputation? · What happens to your file? · English overview