Which Ancestry Came From Your Mother and Which From Your Father From Raw DNA?
A single raw DNA file cannot split autosomal ancestry into maternal and paternal sides; only mtDNA and Y DNA are directly parent-traceable.
Which Ancestry Came From Your Mother and Which From Your Father From Raw DNA?
A single raw DNA file from 23andMe, AncestryDNA, MyHeritage or a whole-genome VCF cannot split your autosomal ancestry into a mother side and a father side. The file records two copies of each marker but does not record which parent contributed which copy. Only mtDNA traces the maternal line directly and, if you have a Y chromosome, Y DNA traces the paternal line directly.
A raw DNA file can give you total ancestry proportions and direct maternal or paternal haplogroups. It cannot label autosomal ancestry as maternal or paternal without extra phase information.
Which of my ancestry came from my mother and which from my father, from raw DNA files?
None of the autosomal ancestry percentages can be assigned to a specific parent from the raw file alone. If a report says you have 48 percent England and Northwestern Europe, that number mixes the contributions from both parents. The raw file underneath has no column for "mother" or "father".
| DNA type | Parent it traces | Why |
|---|---|---|
| Autosomal (chromosomes 1-22) | Neither parent directly | Two copies stored as two letters; no phase |
| mtDNA | Mother only | Mitochondria pass from the egg |
| Y DNA | Father only, if you have a Y | Only biological males carry it, from the father |
Scroll the table sideways for the rest →
Autosomal DNA is unphased in consumer raw files. mtDNA and Y DNA are uniparental, so their parent of origin is direct.
The direct parent-traceable parts are much thinner than most people expect. Your mtDNA haplogroup follows your mother, your mother's mother, and so on. Your Y haplogroup follows your father, his father, and so on. Those are two single lines out of a family tree that doubles every generation.
What your raw file actually records at each marker
A consumer genotyping chip reads around 600,000 to 700,000 autosomal SNPs. At each SNP the file stores two alleles, for example A G. It does not say whether the A came from the mother and the G from the father, or the other way round. Both possibilities produce exactly the same line in the file.
That missing information is called phase. A raw file is unphased. This is not an accident of the format. The chip measures both copies together, so the parent of origin is simply not in the data.
Mitochondrial DNA is a small loop of about 16,569 base pairs. Consumer Y chromosome coverage is much thinner than full Y sequencing, typically a few hundred to a few thousand Y markers, enough for a haplogroup but not a full paternal lineage sequence.
How parent labels get assigned
Phasing separates the two copies into haplotypes, or long stretches of markers that sit together on one chromosome. There are two ways parent labels get attached.
- If you have one biological parent's raw file, many positions become unambiguous. If a parent is
TTand you areCT, theCmust have come from the other parent. - If you are phased against a large reference panel, the software can separate your two haplotypes statistically and label them Parent 1 and Parent 2. Those labels are arbitrary until you connect a parent.
AncestryDNA's SideView does the second thing. It can split your ethnicity estimate into two parental sides without a parent's sample, but it calls them Parent 1 and Parent 2. It does not know which one is your mother. 23andMe can split parental inheritance when a parent is connected to the same account.
The common mistake is deciding that Parent 1 is your father because it appears first. The order is not biological.
What this means for health and trait findings
Most health and trait markers are also autosomal and unphased. A raw file can say you carry one APOE e4 copy, not whether it arrived from your mother or your father. If a parent has tested, you can often figure that out. Without a parent, the report cannot.
Rare imprinting effects, where expression depends on parent of origin, are not resolved by consumer raw files. That is a separate question from what a direct-to-consumer ancestry or trait report is designed to answer.
What to do next
If you want the mother-father split, phase against a parent's raw file or use a service that assigns Parent 1 and Parent 2 statistically. If you only have your own file, read the direct lines for what they are: mtDNA gives the maternal line, Y DNA gives the paternal line, and autosomal ancestry gives the combined picture.
Choosing a file. The report is read on your own device.
Ancestry across 15 regions and 157 reference populations.
The free DNA tool at HealthOS reads raw 23andMe, AncestryDNA, MyHeritage or whole-genome VCF files in the browser. It reports ancestry proportions, closest present-day and ancient populations, a PCA plot, Neanderthal variant count, and maternal and paternal haplogroups, then answers questions about traits, medication response and carrier findings from your own file.
New to raw DNA files? Start with the full guide: How to Download & Analyze Your 23andMe Raw Data Free
Written by
HealthOS Research