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Sveta Kors
Sveta Kors

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Parsing Raw DNA Files: Why 23andMe and MyHeritage Are Incompatible

While working with consumer DNA data, I noticed that many people assume raw DNA files from different providers are compatible with each other. In practice, this is rarely true.

Services like:

  • 23andMe
  • AncestryDNA
  • MyHeritage
  • FamilyTreeDNA

all export genetic data differently.

For example:

23andMe

Uses a TSV-like structure with:

  • rsid
  • chromosome
  • position
  • genotype

Example:

rs3094315   1   752566  AA
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AncestryDNA

Uses CSV formatting and separate allele handling.

MyHeritage

Uses another CSV variant with different parsing expectations.

Even though the biological data is similar, direct upload between services often fails because:

  • column order differs
  • delimiters differ
  • genotype representation varies
  • SNP coverage is inconsistent

I created a small open-source repository documenting these differences and conversion logic between providers.

GitHub:
https://github.com/milaza/dna-raw-data-converter-23andme-myheritage-ancestry/

The repository includes:

  • format explanations
  • conversion examples
  • sample files
  • compatibility notes

There is also an online converter for users who do not want to manually process raw DNA data:
https://tendna.com/en/dna-converter

It was interesting to discover how fragmented consumer genetic data formats still are, despite the growing popularity of DNA testing.

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