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Triple Play: Triangulating Your DNA Matches
Where do you fit in with your DNA matches? Triangulating a known relationship with unknown matches can reveal the answers. We’ll show you how to do it.

dna matches triangulation

Triangulation is a broad term with application in many fields, from psychology to politics. In genetic genealogy, triangulation mirrors the process used by surveyors, who employ multiple triangles to help deduce the exact landscape of a particular area. Genetic genealogists create triangles from groups of three autosomal DNA matches to get a better picture of how each member of the group is related to the others. Commonalities among the three individuals’ family trees may indicate shared ancestors. For example, if two group members have common Smith ancestors in Colonial Massachusetts, the third group member—who perhaps hasn’t yet reached that far back in her tree—might theorize she’s also connected to the Smiths and turn to traditional genealogical records to investigate.

You don’t have to be a DNA expert to start using triangulation to your advantage. You just have to have autosomal DNA test results from one of the four major testing companies (23andMe, AncestryDNA, Family Tree DNA or My-Heritage DNA), a known cousin with autosomal test results, and some shared matches. We’ll show you how to triangulate your way to family tree success.

In this corner … 

While the triangle used to play music and the triangle giving you trouble in math class are very different from the genetic genealogist’s triangle, there are some definite similarities among them: Without fail, every triangle has three sides, connected at three points. Let’s discuss each point in the DNA triangle and how to identify it.

Point A: The first point is you (you’re already a third of the way there!). What makes you the perfect starting point? Well, it’s your DNA of course—your autosomal DNA, the stuff that came half from mom and half from dad. Of your enormous DNA record, the testing companies evaluate about 800,000 pieces. Now stop for just a second to appreciate the strength of your position on this triangle and the significance of those 800,000 pieces. They can identify you uniquely, apart from everyone else in the whole world. Not only that, but these pieces of DNA also form a kind of map of your ancestors and your ancestry. Think of your DNA as various points scattered across time and space, outlining the vast landscape of your heritage. Contained in your very own DNA is a record of the places your ancestors lived, their families, and even their secrets.

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