AncestryDNA Clusters Explained: Making Sense of Your Matches

What a DNA cluster is

A DNA cluster is a group of matches who are likely related to you through the same ancestor or ancestral couple. The usual sign is that the people in the group also match one another, not just you. If you and three cousins all share DNA with each other, there is a good chance you all descend from one shared line.

Clusters are useful because a single match with a vague tree is hard to place, but a match that sits in a group with several people you can identify is much easier to place.

Does AncestryDNA have a clustering tool?

As far as we know, AncestryDNA does not offer an automatic cluster chart in the way some other services do. MyHeritage, for example, offers AutoClusters, which produces a visual grid of matches that match each other. On Ancestry, you build clusters yourself from the tools in your match list, or you use outside tools that work from your match data. Features change over time, so check Ancestry’s current help pages if something here looks different on your screen.

The Ancestry tools you can use

• Shared Matches: Open a match and select the shared matches view to see people who match both you and that person. Ancestry generally limits this view to more distant matches above a minimum amount of shared DNA, so very small matches may not appear.
• SideView: Ancestry can sort many matches into maternal and paternal groups. These first appear as “Parent 1” and “Parent 2” until you label them. See what Parent 1 and Parent 2 mean for how to identify each side.
• Custom groups, notes and stars: You can place matches in color-coded groups and add notes. These work well as manual cluster labels, for example “Grandma Rossi line”.
• Trees and ThruLines: If a match has a linked tree, a shared ancestor can tell you which cluster the person belongs to. Read how accurate ThruLines are before relying on them.

Building clusters by hand

1. Start with a close or well-understood match, such as a first or second cousin whose connection to you is clear.
2. Open that match’s shared matches and add each person to a group named for the ancestral line.
3. Open the shared matches of those people too, and add new names to the same group when they clearly belong.
4. Look at the trees of the group members and note common ancestors or locations.
5. Record what you learn in notes so you do not have to repeat the work.

A well-known version of this approach is the Leeds Method, which sorts matches into color-coded groups by grandparent line. It is slow, but it works with only the tools Ancestry provides.

Third-party clustering tools

Several outside services build cluster charts from match data that you collect or export from your account. Some use browser extensions or data you upload. Before using any tool, read what data it collects and how it handles your login or match information. Ancestry’s terms and your privacy matter more than convenience, and tools that scrape pages can stop working when the site changes.

Reading a cluster

• A tight cluster of matches who all share DNA with one another suggests one common ancestral line.
• Two clusters that touch through a few people may point to a relationship between two branches of your family.
• If a group has a single known member with a documented tree, the others likely connect through that tree as well, though this is a clue and not proof.

Common pitfalls

• Both-sides matches: Some matches can appear to connect to both parents’ sides. See finding your mother’s and father’s sides for why this happens.
• Endogamy: In communities where many people married within the same small group, nearly everyone matches everyone, and clusters blur. The Jewish ancestry DNA test guide explains why this is common with Ashkenazi ancestry.
• Small matches: Low shared amounts can be coincidental, so be careful building a cluster on very small segments.
• Wrong labels: An incorrect relationship guess can mislead the sorting. Read about changing a relationship label and how half siblings show up, since close matches anchor your clusters.

FAQ

Does Ancestry show clusters automatically? Not as a built-in chart, to our knowledge. You use Shared Matches, SideView and groups, or an outside tool.

Is a cluster proof of a relationship? No. It is a lead that points toward a shared ancestor and still needs records or tree evidence.

Which match should I start with? A close match whose relationship is certain makes the best anchor.