How are DNA Circles created?
A DNA Circle is a group of individuals who all have the same ancestor in their family trees and where each member shares DNA with at least one other individual in the circle. These circles are created directly from your DNA and your family tree in a five-step process.
- Find DNA matches
We compare your DNA to the DNA of every AncestryDNA member. When we find enough shared DNA to suggest that you and another member have inherited that DNA from the same recent ancestor, we consider you a “DNA match.” Based on the amount of DNA you share, we then estimate your relationship (for example you may be 5th or 6th cousins).
- Search trees for shared ancestors
Once we’ve found a DNA match, we carefully search both of your family trees looking for ancestors who appear to be the same person. We consider facts like name, birthdate, birthplace, parents, and spouse (going back nine generations).
- Calculate a shared ancestor hint confidence score
We consider a variety of factors to determine how likely it is that you and your match share DNA from this same ancestor (as opposed to sharing DNA common to a region, or sharing DNA from a different ancestral line). (Learn how confidence scores are calculated for Shared Ancestor Hints).
- Add more people to the DNA Circle
Now, we repeat the process and look for other pairs of individuals who have the same shared ancestor in their trees and who share DNA with one or more of existing circle members (each circle has at least three members). Some of these new members may not share DNA with you, but each member of the circle has DNA evidence supporting their relationship to the share ancestor, and therefore to you. (Learn more about who you’ll find in a DNA Circle.)
- Calculate connection levels
Last, we figure out a connection level for every member of the circle based on the number of people they match in the circle and the strength of their connections. It’s a simple way to show how likely it is that each member is a descendant of the shared ancestor. Levels go from Strong to Good, Weak, or Emerging. (See how we calculate connection levels.)
Circle Membership Confidence: Strong
DNA Circles will change over time
You’ll notice that DNA Circles are constantly evolving. A circle could grow, shrink, or even disappear. And new circles will be created too. This all happens for a couple reasons. First, AncestryDNA members are constantly growing and improving their family trees. Second, as new people take tests and join AncestryDNA, we have even more information to analyze and use to improve our circles and help you fill in even more pieces of your family history puzzle. (Find out how DNA Circles can change over time.)
Note: What if you aren’t a member of a DNA Circle for one of your ancestors? One possibility is that you descended from the ancestor, but you didn’t inherit DNA from them (see how this can happen). Another explanation is that more descendants need to take the AncestryDNA test before there’s enough evidence to create a circle.