The DFA now documents 199 confirmed family groups — a number that has grown steadily, article after article, as new Family Group Sheets are researched and added. The Dillman DNA Project has not grown with it. Twenty-one groups participate today. Twenty-one groups participated when the dataset was 160 groups. Twenty-one participated when it was 94. Three expansions, well over a hundred newly documented families, and not one of them has added a single new DNA participant.^[1] That gap is the entire subject of this article: why it matters, and what it will actually take to close it.

Why Y-DNA, Specifically

Not all DNA testing serves the same purpose, and for a surname project like this one, the specific test that matters is Y-DNA. The Y chromosome passes from father to son almost entirely unchanged, generation after generation — the same pattern of inheritance, down the same male line, that carries a surname in most Western naming traditions.^[2] That overlap is what makes Y-DNA testing uniquely suited to a project like the DFA’s: two men who share a documented Dillman surname and a closely matching Y-DNA signature are almost certainly connected through that same paternal line, whether or not any surviving paper record proves it.

Only men carry a Y chromosome to test directly. A woman researching her Dillman ancestry can still contribute to this effort, but she’ll need to find a father, brother, paternal uncle, or paternal male cousin along that specific line willing to test on the family’s behalf.^[3]

What’s Actually at Stake

This isn’t an abstract call for more data. The DFA’s own research has already identified at least twelve genetically distinct Dillman lines, confirmed by the DNA testing done so far, with no single common ancestor connecting them.^[4] That finding is powerful specifically because so few groups have tested — which means it likely understates the real picture. Every additional participant is a chance to answer a question no paper record can: whether two documented family groups, separated by an ocean or a century with no surviving connection in the written record, actually share a common paternal ancestor. Whether a family group with an incomplete or uncertain origin — and the DFA has several — belongs to one of the already-documented lines or represents an entirely new one. These are exactly the kinds of questions a single well-placed Y-DNA test can resolve, when no combination of archival research ever could.

Every family group not yet in the DNA project is a specific, answerable question sitting unanswered — not because the answer is unknowable, but because no one from that line has taken the test yet.

Why Participation Has Stalled

The flat number across three expansions doesn’t mean people don’t care. It more likely reflects the ordinary reasons any volunteer effort stalls: many family group contacts simply don’t know the DNA project exists, or don’t know it applies to them specifically; the cost of a test is a real barrier for some; and without a clear, specific ask — not “more participation would help” but “this exact family line needs a tester” — it’s easy to assume someone else will get to it eventually. That last problem has a concrete fix, and it’s the second half of this initiative.

Introducing DFA Most Wanted

Starting this week, the DFA is launching a new weekly feature: DFA Most Wanted, a short, recurring spotlight on one specific family group that has no DNA representation yet — who the ancestor was, what a test from that line could resolve, and how to get in touch if that’s your family. The goal is simple: replace a vague, general appeal with a specific, answerable one, one family group at a time, published often enough that the whole documented database gets its turn. Every group that’s already been featured will be tracked to avoid repeats, so the series builds real, cumulative coverage over time rather than circling back to the same few names.

How to Participate

• Take a Y-DNA test. The Dillman DNA Project is hosted at FamilyTreeDNA, which offers Y-DNA testing at several marker levels (Y-37, Y-111, and the more comprehensive Big Y-700). Any level contributes real value; a higher level gives sharper, more specific matching.^[5]
• Join the Dillman DNA Project at FamilyTreeDNA so your results are grouped and compared directly against other tested Dillman lines, not just the general public database.
• If you’re not a direct male-line descendant, find one. A father, brother, uncle, or male cousin along the correct line can test on behalf of the whole family group.
• Contact the project administrator at dnaprojectadmin@dillmanfamilyassociation.org with questions, or to let the DFA know your family group is ready to be tested.

Twenty-one participating groups out of 199 documented is not a verdict on this family’s interest in its own history — the volume of research behind every article in this series proves otherwise. It’s a gap that a few hundred people, tested a handful at a time, can close. If your family group isn’t one of the 21 yet, this is the invitation.

Sources

1. Dillman Family Association, Family Group Sheet Database, compiled 2026; Dillman Family Association, “What the Numbers Tell Us” series (2026).
2. “Y Chromosome DNA Tests,” ISOGG Wiki (accessed July 2026).
3. “Y-DNA Test: What Is a Y Chromosome Test and Which Is Best,” Genealogy Explained (accessed July 2026).
4. Dillman Family Association, “What the Numbers Tell Us: A Statistical Portrait of the Dillman Surname” (2026).
5. “Trace Your Paternal Ancestry With Y-DNA,” FamilyTreeDNA (accessed July 2026); “FamilyTreeDNA in Genealogy Research,” FamilySearch Research Wiki (accessed July 2026).

AI Disclosure: This article was researched and written with the assistance of Claude, an AI assistant developed by Anthropic. General claims about Y-DNA testing are drawn from the sources cited above; DFA-specific claims are drawn from the association’s own Family Group Sheet Database and prior published articles.

Notes

1. DNA participation figures are drawn from the Dillman Family Association, Family Group Sheet Database, compiled 2026, cross-referenced against the “What the Numbers Tell Us” article series.