How to Cite a DNA Test Result as a Source

 DNA testing has become one of the most powerful tools in genealogy. But when you use a DNA result to support a conclusion in your research, you need to cite it — and most people have no idea how. A DNA test is a source, just like a census record or a death certificate. It needs the same disciplined citation that any other piece of evidence receives.

What You Are Actually Citing

When you cite a DNA test result, you are citing a specific test taken by a specific person on a specific platform, showing a specific result on a specific date. DNA results are not static — testing companies update their algorithms, recalculate ethnicity estimates, and add new matches over time. The result you see today may not be the same result someone sees next year. Your citation needs to pin down what you saw and when you saw it.

The Components of a DNA Citation

A complete DNA citation should include: the testing company (AncestryDNA, 23andMe, MyHeritage, FamilyTreeDNA, etc.), the name of the person tested (or a descriptor if privacy is a concern), the type of test (autosomal, Y-DNA, mitochondrial), the specific result you are citing (a shared cM value, a predicted relationship, an ethnicity estimate, a haplogroup assignment), and the date you accessed the result.

For a DNA match, you should also record the shared centimorgans (cM), the number of shared segments, and the predicted relationship as stated by the platform. These numbers are the raw data that support your interpretation.

A DNA citation follows this pattern: [Testing company], [type of test], [person tested] (test administered [date or approximate date]); [specific result cited]; accessed [date]. For matches: include shared cM, segments, and predicted relationship.

Why the Access Date Matters

Testing companies regularly update their relationship prediction algorithms and ethnicity estimates. A match that was predicted as "4th cousin" in 2022 might be predicted as "3rd–5th cousin" in 2025 after an algorithm update. An ethnicity estimate that showed 25% Irish in 2020 might show 22% Irish after a reference population update. The access date establishes which version of the result you were looking at.

Citing Shared Matches and Triangulated Groups

When your argument depends not just on one DNA match but on a group of shared matches or a triangulated segment group, your citation becomes more complex. You need to document each match in the group, the shared cM values, and how they connect. This is best done in a research note or proof summary that explains the analysis, with individual citations for each match.

A triangulated group — three or more people who all share DNA on the same chromosome segment — is strong evidence that they inherited that segment from a common ancestor. But the citation needs to document each match and the chromosome browser data that proves the triangulation.

Screenshot your resultsDNA platforms change their interfaces, update their algorithms, and occasionally remove features. Screenshot every result you cite — the match page, the shared cM value, the chromosome browser view, the ethnicity breakdown. Save these screenshots with your research files. They are your evidence.

DNA as Evidence, Not Proof

A DNA result is evidence — it contributes to a conclusion. It is rarely proof by itself. A shared cM value of 200 cM is consistent with several possible relationships (first cousin twice removed, half first cousin, second cousin). The DNA tells you the two people are related within a certain range. You need paper records to determine the specific relationship.

When you cite DNA in your research, make clear what the DNA evidence does and does not establish. "AncestryDNA test of [person] shows 850 shared cM with [match], consistent with a half-sibling or grandparent/grandchild relationship" is an accurate, evidence-based statement. "DNA proves [person] is the grandchild of [ancestor]" overstates what the DNA alone can demonstrate.