Last week we announced an exciting new AncestryDNA feature called “New Ancestor Discoveries.” The response to this feature launch has been very interesting to watch—we’ve received lots of feedback breathless with praise because we “proved” a relationship, and some feedback that dismisses the feature because it does not “prove” relationships. As we consider feedback from both of these extreme positions, it seems appropriate to explain more clearly what this feature is and is not.
What is a New Ancestor Discovery?
- What it is: A New Ancestor Discovery is a suggestion that points you to a potential new ancestor or relative—someone that may not be in your family tree previously. This beta launch is our first step toward an entirely new way to make discoveries, and a way to expand how we do family history.
- What it isn’t: This is not proof, or a guarantee, of a new ancestor. They’re called New Ancestor Discoveries, and many may be your actual ancestors. Some will be other relatives that fit somewhere on your family tree, and some will be people that you may not be directly related to.
- It’s a starting point to further research. We’ll show you a New Ancestor Discovery if you share significant amounts of DNA with multiple members of a DNA Circle—which means you might also be related to the ancestor that the DNA Circle is built around. These hints can be a great starting point for your research and help you connect to other family members you didn’t know you had.
Why do we think you are related to this person?
- The short answer is that we don’t know for sure. What we do know is that you share significant amounts of DNA with others who are likely descendants of the ancestor, which leads us to believe that there is a good chance this person could also be either your ancestor or a relative.
- When considering if you might be related to a potential ancestor or relative, we combined several pieces of information to make that determination: the number of people in the DNA Circle with whom you share DNA, the amount of DNA shared with each DNA Circle member, the number of generations back to the ancestor for each individual in the Circle, and our confidence that you and each member of the Circle share only one common ancestor.
- The number of members of a DNA circle that you match directly influences how strongly you appear to be a descendant of an ancestor. Also the size of the DNA Circle (in terms of the number of members) can also influence how you interpret your confidence in the potential relationship. A small group of say 3 – 5 members might potentially grow in size as more people participate in the DNA test, but should be considered as an emerging evidence of a genetic relationship until it grows further.
- A New Ancestor Discovery is created as we detect that you share significant amounts of DNA with several members of a DNA Circle—which means you might also be related to the ancestor that the DNA Circle is built around.
What is the confidence you are really related to this person?
In general, the confidence that a New Ancestor Discovery really fits in your family tree is pretty good—about 70%. However this can vary in each individual case. Also it is important to understand that while some New Ancestor Discoveries lead to a direct ancestor, some suggested ancestors end up belonging in your family tree as a collateral line relative, and some won’t be closely related to you at all—but they likely lived at the same time and place as your actual ancestors so they could be a helpful clue to point you in the right direction.
In addition, the ratio of new ancestor vs. collateral line relatives can vary based on how many DNA Circles you are already connected to through your family tree. We find that people who have stronger family tree connections (and so generally have more connections to DNA Circles) will see a much larger proportion of collateral line relatives or suggested ancestors that don’t clearly fit in your tree, but lived at the same time and place as your actual ancestors. The reason for this is that when you have an extensive family tree, we typically have already identified your direct ancestors in a DNA Circle.
Because of all this, it is important to apply traditional family history research methods to each potential ancestor suggested by a New Ancestor Discovery in order to determine more specifically how you might be related.
How is the confidence determined?
To determine this confidence percentage we performed tests of our algorithm on a massive set of DNA tests where a nearly-complete and deep pedigree is known. We remove each individual’s pedigree data in our analysis and find New Ancestor Discoveries for each DNA test. Then we look again at the pedigree information we previously ignored and compare what New Ancestor Discoveries we found versus what actual ancestors exist in the pedigree, and what collateral-line relatives are observed. This analysis gives us confidence that, in general, if you have an empty family tree, the ancestors and relatives we suggest in this process are likely to belong in your family tree as a direct ancestor or as a collateral-line relative about 70% of the time.
An exciting journey of discovery
We are very excited about the many family history discoveries that are being made now and will be made in the future as the New Ancestor Discoveries feature continues to grow and improve. Please keep sharing your feedback with us — we are definitely listening. And if you haven’t taken the AncestryDNA test yet, now is a great time to begin.