Sorting DNA matches into family lines

A new DNA match list can run to thousands of names, most of them distant cousins with unfamiliar surnames, and scrolling through it rarely leads anywhere. Sorting DNA matches into family lines first gives you a map: you learn which matches belong to your mother's side, which to your father's, and which branch to research next.

Why sorting DNA matches comes before searching

An autosomal DNA test cannot tell you which parent a match is related through. Two matches with similar amounts of shared DNA could sit on completely different branches. Grouping matches by line lets you focus on one set of ancestors at a time, and it stops you building a tree for a match you have put on the wrong side.

Step 1: Identify your anchor matches

Anchor matches are relatives whose place in your tree you already know: a first cousin, an aunt, a half-sibling or a parent who has tested. Everyone else gets placed in relation to them.

• Look for close matches with recognisable names near the top of the list.
• Confirm the relationship using the shared centimorgan figure and a relationship chart such as the Shared cM Project ranges.
• If you can, find at least one anchor on each grandparent's line.

If a parent or grandparent is willing to test, their results make a strong anchor, because every match they share with you belongs to their side.

Step 2: Use shared matches

Most testing sites show a "shared matches" or "in common with" list. Open an anchor match and review everyone you both match. Those people are likely related through the same line.

A simple workflow

1. Open your maternal anchor and view shared matches.
2. Label each shared match with a colour or tag for that line.
3. Repeat for your paternal anchor, then for each grandparent line if you have anchors there.
4. Leave matches that appear under more than one anchor unlabelled for now; they need a closer look.

Step 3: Choose a labelling system and keep it

Many researchers use four colours, one per grandparent. Others prefer short text notes. Either works if you apply it the same way every time, so a label still means the same thing six months from now.

• Use the site's built-in groups or colour dots if it offers them.
• Keep a spreadsheet with match name, shared cM, number of segments, line and notes.
• Record why you placed each match, for example "shares with cousin Ann (maternal)".

Step 4: Look at trees and surnames

Once a group of matches sits on the same line, compare their family trees. Surnames or places that repeat across several trees often point to the shared ancestral couple. A surname that appears in five trees in the same county is a lead to check in the records.

Common pitfalls

• Very small shared amounts can be harder to place reliably, so work on larger matches first.
• In communities where families intermarried over generations (endogamy), matches can share DNA on several lines at once and look closer than they are.
• If many matches fit no known line, the explanation may be an adoption or an unrecorded parent somewhere in the tree. Approach that possibility carefully.

A quick checklist

• At least one confirmed anchor on each side.
• Shared matches labelled by line.
• A spreadsheet or notes recording each placement.
• Surnames and places compared across a group's trees.

Where to go next

With matches grouped, pick one line and build the trees of its top few matches back until they meet yours, then confirm each generation with records. The homepage section on reading matches and centimorgans explains why one cM figure can fit several relationships, and reading a census return column by column helps with the document side. Most testing services, including MyHeritage, offer shared-match views and labelling tools, and the method above works the same way on any of them.