Raw DNA file check

Consumer testing companies each export raw data in their own text format, with different column layouts, different marker naming and very different marker counts. This diagnostic parses the file you give it, reports which vendor format it detected, counts the usable markers it found on each chromosome, and states which of our analyses can actually read it. It is a read-only check: nothing is ordered, and the file is deleted once the report renders.

Marker count is the number that decides what a file can support, and it is the one nobody is told. Autosomal marker density governs how precisely an admixture model can be fitted; the Y-chromosome and mitochondrial rows govern whether a paternal or maternal haplogroup can be read at all. Files from the same company differ by chip generation, and some products carry no Y rows whatsoever — which is why a file can work perfectly for one analysis and be unusable for another.

Seeing the per-chromosome breakdown before you buy anything is the point. A file thin in autosomal markers will still produce an admixture model, but with wider standard errors, and no amount of analyst effort recovers coverage the file never had. What this check cannot do is judge the data's quality beyond what the file states: it counts what is present and reports the format, but cannot detect a mislabelled sample, a mixed-up kit, or genotyping error in individual calls. Runs need a free, email-verified account.

Suppose the check reports: 23andMe v5 detected, ~630,000 autosomal markers spread evenly across chromosomes 1–22, ~3,600 Y-chromosome rows, ~4,000 mitochondrial rows — verdicts: qpAdm yes, Ancient Matches yes, Global25 route yes, paternal haplogroup yes. That is the healthy-file shape: a current-generation chip with dense autosomes and enough uniparental rows for haplogroup calls. The number that matters most downstream is the autosomal count, because standard errors in formal models are set by how many of those markers survive the merge with the ancient panel — coverage is the ceiling no analyst effort raises.

Now the common deviations and what each means. A file with zero Y rows is not broken — several products ship exactly that — but the paternal-haplogroup verdict will honestly read no, whatever the customer expected. A file whose marker count lands far below its vendor's usual range is typically an older chip generation or a truncated download; re-exporting from the vendor fixes the second, nothing fixes the first. And a whole-genome VCF reads differently by design: variant counts rather than fixed positions, with the verdicts reflecting the conversion our uploaders perform.

The habit this page exists to create: run the diagnostic before paying anyone — us included. Every refusal our order flow makes on file grounds is visible here first, for free, which is cheaper for everybody than a refund conversation.

The usual alternative is no diagnostic at all: buyers assume a '23andMe file' is one fixed thing, when marker sets differ across that company's five chip generations by hundreds of thousands of positions. The second alternative is the analyzer-and-converter ecosystem (DNA Kit Studio and its kin, or DNA Genics' file tools), which inspects and rewrites raw files ably but answers a different question — those tools report what a file contains generically, where this page answers the question a buyer actually has: which specific analyses can this file support, stated per product against the panels those products really merge with.

What no checker anywhere can promise: that the DNA in the file is the person on the label, that the vendor's calls are error-free, or that a file good for one analysis is good for all. The honest scope is exactly what is printed — format, counts, per-analysis verdicts — and the file itself is deleted once the report renders.