Solving DNA Puzzles with Triangulation

DNA is the future of genealogy, or at least that’s what everyone had been telling me. Which is why I did an Ancestry DNA test in 2019. To support my DNA results, I uploaded my tree to Ancestry and made it public so that anyone who has an Ancestry subscription can view it.

In previous posts I explained how I used DNA to solve several puzzles. Encouraged by these successes and with the help of friends who’d been using Ancestry’s DNA tools for a few years, I began exploring. I reviewed the ThruLines, which help you find out if ancestors in your tree appear in the trees of your DNA matches. I learned to use the DNA match search, which lets you search the trees of your matches by surname and also by locations that appear in their trees.

Disappointingly, not all of my matches had a tree on Ancestry and some of those who did have trees had them set to private rather than public. Without a tree or a surname match, how could I determine the relationships with my matches? That is when I discovered triangulation.

If I was reviewing a match who did not have a tree and I didn't recognize any information (name of the match, for example), I then looked at 'shared matches.' This brings up a list of all my DNA matches who also matched with the person in question. If I were lucky, one of the shared matches would have a tree that would tell me how they fit into my tree. Then I could look at the relationship between those two matches to see how much DNA they shared and what their predicted relationship was to each other and thus how the person in question might be related to me.

This process is called triangulation. The person at the top of the triangle is me. The person on the right is the person in question, the person on the left is the shared match. In the middle is our shared ancestor.

But if none of the matches had a tree, I had to continue the triangulation by looking at the shared matches of the shared matches. If I kept triangulating shared matches, eventually I was able to figure out how we were related or at least on which branch of the family.

Using triangulation, I identified mystery matches and even grouped and colour coded my matches by family line for easier reference. And I sent messages — lots of messages. Most of the time I got no reply. Other times I’d get a reply, but the person had less information than I had and wasn't really interested in research.

For more information on triangulation in genetic genealogy visit one of these websites:

https://www.yourdnaguide.com/ydgblog/2019/7/2/dna-triangulation

https://www.familytreemagazine.com/premium/triple-play-dna-matches-triangulation/#

https://thegeneticgenealogist.com/2016/06/19/a-triangulation-intervention/