Common Ancestors Gold EAP

Overview

Common Ancestors works from the family trees gathered for a kit's DNA matches. It does two things:

It lists the kit's matches with the ancestor each one shares with the tester, when the trees show one.
It scans all the match trees together for ancestors that two or more matches descend from, whether or not those ancestors are in your own tree yet. These are the leads for a line you have not worked out.

The page is in the Client under People > Common Ancestors and is a Gold feature.

What You Need

Match trees. Gather the kit with tree gathering turned on. A match with no tree cannot contribute.
A reference tree, if you have one. This is the tester's own tree, assigned to the kit in My Trees or from this page. With it, the page can tell you which shared ancestors are already yours. Without it the page still lists the matches and can still scan their trees against each other.

Choosing a Kit and a Reference Tree

The first time you open the page, a window asks you to pick a kit. After that the page opens on the kit you used last; click the DNA Kit button on the left to change it.

In that window:

Pick the kit under Select Kit. Each kit shows where it stands: how many ancestors were found, Ready to compute, or Assign a tree.
Optionally pick the tester's tree in the list below and click Assign as Reference. You can skip this if you have no tree of your own.
Click Recompute Ancestors after assigning or changing a tree.
Click View Ancestors to load the kit.

Add as Enrichment attaches another GEDCOM to the kit as a helper: for example a cousin's well-researched tree. It fills gaps that the reference tree and the match trees leave, without overriding what the match trees say. A kit can have several.

A green bar at the top of the page names the reference tree in use. An orange bar reading No reference tree means none is assigned; its Assign reference tree button opens the same window.

The Match List

Column	What it shows
(tick box)	Ticks the match for comparing.
Match Name	The match.
Shared cM / Segments / Relationship	What the testing company reports.
Tree Source	Where the match's tree comes from and how many people it holds, for example “Match (12)”. The small icon beside it opens the match's tree.
Father / Mother	The match's parents, from their own tree.
Common Ancestor(s)	The ancestor or couple this match shares with the tester. “(ThruLines)” marks one the testing company itself suggested.
Exclude / Restore	Leaves a match out of the analysis, for instance when their tree is plainly wrong. Tick Show excluded to see them again.

Filters

Match Name — part of a match's name.
Ancestor Name — part of an ancestor's name, or of the match's father's or mother's name.
cM Range — from and to, to look only at closer or more distant matches.

Filters apply as you type. The count under them shows how many matches are listed.

Opening a Match's Tree

Double-click a match to see how they fit: their line drawn up to the ancestor they share with the kit. See Compare Match Trees for how to read that view.

Comparing and Scanning

The purple button under the filters changes with how many matches you have ticked:

Ticked	Button	What it does
One match	Compare to all matches	Finds the ancestors that match shares with any other match of the kit.
Two or more	Compare selected	Opens the ticked matches' trees together in Compare Match Trees.

Scan All for Common Ancestors — looks through every match with a tree for ancestors shared by two or more matches.
Scan Shared Matches of Highlighted Match — click a match's row first. Scans only the matches that match shares with the kit, which is a good way to work on one branch at a time.

The first comparison or scan for a kit builds one combined tree from all of the kit's match trees. A box reading Working… shows progress. On a kit with thousands of match trees this takes around fifteen seconds; after that the kit's tree is kept ready until you leave.

Common Ancestor Discoveries

A scan opens the discoveries list: one row for each ancestor that two or more matches descend from.

Column	What it shows
Ancestor, Years, Birth place, Death place	Who the shared ancestor is.
Matches	How many matches descend from them.
Largest cM / Total cM	The most any one of those matches shares with the kit, and the sum for all of them.
In tree	“In your tree” when the ancestor is already in the kit's reference tree.
Matches (cM)	The matches themselves, largest first.

Sort by Matches or Total cM to bring the best-supported ancestors to the top. An ancestor many matches share who is not in your tree is where to look next.

Narrowing the List

Search — an ancestor's or a match's name.
Parent side — for A* kits, keep ancestors whose matches are on the Father's or Mother's side, or in one of the two unlabelled parent groups.
Match level — how strictly names are compared: Level 1 (exact name), Level 2 (first name, recommended) or Level 3 (initial and year). Changing it runs the scan again.
Hide ancestors already in my tree — shown when a reference tree is included; hides ancestors that are already in it.

Working With a Row

Double-click, or right-click > Drill in — opens Compare Match Trees on that ancestor, showing how each match descends from them.
Right-click > Open person page — opens the ancestor in People, adding them if they are not there yet.
An orange ❓ candidates badge means some matches might belong to this ancestor: the name and dates are close, but nothing in the trees confirms it. Click the badge to look at the two side by side and decide. Candidates are not counted in the cM columns until you confirm them.

Exporting

Export CSV and Export PDF save the rows shown. Export Full Tree (GED) saves the kit's whole combined tree as a GEDCOM file, which can be large.

Exporting the Match List

On the Common Ancestors page itself, PDF saves the matches listed with their shared ancestors, and GED saves them as a GEDCOM file you can open in a genealogy program as a starting point. The ⧉ button opens a second copy of the page in its own window, so you can look at two kits side by side.

Tips

Trees on the testing sites are other people's work and can be wrong. A shared ancestor is a lead to check, and several matches agreeing is better evidence than one.
If a kit shows few results, check how many of its matches have trees: gather again with trees turned on.
Exclude a match whose tree is clearly mistaken, so it does not distort the scan.

Compare Match Trees — the combined tree and how to correct it.
My Trees — loading and assigning your own tree.
People — the matches as people.