My Most Used Genealogy Tool: DNA Painter’s Shared cM Project Tool

Best Genealogy Tool for DNA Matches: DNA Painter’s Shared cM Project Tool

​When it comes to genealogy, I find myself consistently relying on one invaluable tool: DNA Painter’s Shared cM Project tool. This tool, developed by genetic genealogist Blaine Bettinger and hosted on DNA Painter, has become essential for mapping out DNA match relationships, whether in my personal family research or client cases. The Shared cM Project tool is simple in design, yet it offers powerful insights by estimating the range of possible relationships between DNA matches based on the number of shared centimorgans (cM).

Why I Use the Shared cM Project Tool So Often

Genealogical research is often like solving a complex puzzle where relationships and connections can be tricky to pin down, especially when it involves unknown parentage or unknown ancestors. When I’m working with DNA test results, whether for my family history or a client’s case, the Shared cM Project tool helps guide my analysis. It’s especially useful when I need to hypothesize the possible relationships between DNA matches and where they fit in, such as estimating whether someone is a likely second cousin, third cousin, or even further removed.

How the Shared cM Project Tool Works

The Shared cM Project tool works by allowing you to enter the amount of DNA (in centimorgans) shared with a particular match. Based on this input, the tool suggests a variety of possible relationships between you and the DNA match, along with the relationship probabilities (%) and a chart for those who are more visual, using data collected from thousands of known relationships. For example:

• If a DNA match shares around 50 cM with you, the tool will suggest that this person could be a potential half-third cousin (Half 3c) or even a half-second cousin twice removed (Half 2c2r), along with many more possible relationships.

DNA Painter Shared cM Project Tool- Example 1-1

DNA Painter Shared cM Project Tool- Example 1-2

• For higher shared cM values, say 800 cM, the tool might suggest closer relationships like first cousin (1c) or half-aunt/uncle, along with a few others.

DNA Painter Shared cM Project Tool- Example 2-1

DNA Painter Shared cM Project Tool- Example 2-2

​In complex cases with multiple DNA matches, the tool’s ability to highlight likely relationships can make a big difference in narrowing down the family tree branches I need to explore.

Real-World Examples of DNA Painter’s Impact in My Research

One example where DNA Painter’s Shared cM Project tool proved invaluable was during a recent client case involving unknown parentage. The client’s DNA results showed a close match with someone sharing approximately 426 cM, with Ancestry predicting them most likely as a 1st cou