About the Saint-Clair DNA Study

UPDATE: March 28, 2023:
Two big pieces of news about St Clair Research:

  1. The re-launched, and re-focused website
  2. The affinity study is yielding results

Year DNA Study Founded


YDNA-tested members




Years of Saint-Clair History

By Steve St. Clair

The first DNA tests for the Sinclair family were completed in the winter of 2004. Now we’re managing over 650 tests from Saint-Clairs around the world. When I talked Stan St. Clair into taking the test with me, we were simply trying to prove whether or not I connected to Stan’s line as he had a solid paper trail to Alexander Sinkler, the 1698 immigrant from Scotland, and my trail had holes in it in the 1800’s. We  proved our connection and since then the study has helped many people find ways around their genealogy brick walls, and learn a lot more about their history.

We voluntarily help members understand their DNA results and how to further their study. Our testing lab, Family Tree DNA is a for-profit company, which is why they’ve been able to advance the science of genetics for genealogy far beyond what we ever thought possible.

Our DNA study is administered by Steve St. Clair and Danny Redmond. When you join the study, we’ll be the ones helping you understand which of the lineages you fit into and guiding you to the next steps. Depending on where you match, we will likely recommend you also join one of the online groups studying your particular DNA SNP.

You might also want to join a matching affinity group. For our Caithness lineage, a logical one would be to keep an eye on the Cummings DNA study since there’s a clear paternity match with them back in the 1100s. The Herdmanston group should keep an eye on the Forrester DNA study.

DNA without historical research can be interesting, but nowhere near as valuable as when done in conjunction with solid historical records.

Early on, Stan St Clair, a distant cousin of mine, helped recruit thanks to his years of work with the clan members. Mark Sinclair Staveley has also been a continuing inspiration in how to run the study more scientifically.

Along the way, we’ve benefited from other documents researchers like Peter Sinclair of England, who has also published a tremendous book on the St Clairs of medieval England, called Medieval Walkern and Magna Carta. He maintains an interesting website on his work (here).

We’re always looking for advice from those who know more about this rapidly changing science than us, and there are many.

A documents researcher and author who helped our Alexander Sinclair Lineage tremendously was Jean Grigsby. She did 35 years of work tracking down the lineage of our 1698 immigrant, Alexander Sinkler from Glasgow.

Researchers like Antonia Sinclair, Peter (Argyle) Sinclair, Rand Greubel and so very many others like Lilian St. Clair Blackford, and Leonard A. Morrison have done and continue to do the heavy lifting of documents research. To you we owe the greatest debt of gratitude. I hope you realize how much you’ve added to this study. On so many pages of this report you’ll read the words – ‘DNA without solid documents research is simply a string of numbers.’  Your work has made it so much more than that for all of us.

No one deserves our gratitude more than the members of the family themselves who donated their very DNA, both to help us understand their lineages and to help others with poor documents research connect to those with good paper trails. I believe that, one day, everyone in our family will say a quiet ‘thank you’ to these hundreds of brave explorers who stepped into the unknown together to make their mark on Sinclair history.

Studying Affinity Families

Surnames were not fixed in the early medieval period. People would change their name when they moved to different land. Steve was one of the first researchers to use a combination of DNA SNP matches combined with medieval benefaction records to explore the likelihood that people with different surnames had a blood relation, or at least intermarried.

A Note on the Spelling of the Name

Throughout the website, you’ll see us bouncing around with different spellings of the name. This is in part because the name changed over time. Here are the criteria for the spellings: 1. Be accurate – If we’re quoting historical documents, we’ll use the spelling from the document.  2. Be inclusive – If we’re talking about the wider family as a whole, I tend to use the spelling Saint-Clair.  3. Support the study – Most of those who find their way to us do so by typing in a search like “Sinclair DNA.” You’ll see us at or near the top on many variations of that search. For that reason, you may see us using that spelling more than any others. The reason is that Sinclair is the most-used variant of the surname. More members means more data and higher accuracy.

Over time, our name started out in the documents with spellings like St Cler and Saint-Clair. Then in England and Scotland, it began to change, even in different records regarding the same man we see different spellings. The generally accepted rule has been that the spelling in France was St Clair and by the time it got up into northern Scotland it had been changed to Sinclair.

What We Are, and What We’re Not

We are a volunteer group who helps those who have (or suspect they should have) some variant of our surname find real connections that get around genealogy brick walls. We guide both men and women to the right testing solution.

  • We are highly interested in finding inventive ways to connect our lineages to medieval people with some variant of our surname.
  • We are not a group that believes the book The DaVinci Code is real. There is not a DNA type that identifies descendants of the Templars. The order drew members from all walks of life.
  • We are not seeking noble status. If you’ve been at this a while, you know why I make this point.
  • We are absolutely resolved to find the truth of where people connect and tell the true story of our family, wherever that may lead.

Please let us know if you’d like to see some subject covered on the website that would benefit others in the family.