Using DNA testing with tools: Gworks, DNA2Tree, and Clustering to Solve Unknown Parentage Cases


All my slides are at

Step 1: TEST your DNA:

at Ancestry and 23andme then transfer to the others

Upload the Ancestry DNA results to other sites for free to get more matches:

  • MyHeritage*
  • Family Tree DNA **
  • GEDmatch
  • LivingDNA (primarily British, not many matches yet)

**$19 for the full tools

*  $29 for the full tools

How does testing your DNA help?

You get half your DNA from each parent, about a quarter from each grandparent and so forth if enough biological relatives are tested you can figure this out

More likely you will need to figure it out from cousin matches

Chart from the ISOGG wiki  (courtesy Dimario, Wikimedia Commons)

The "G" trick

The cousin level = the number of "G"s , else the greats plus one

If you are in different generations take the shorter path and the other is removed by the generation difference

If your roots are deeply American, you may only need to test at Ancestry

Any of these matches may resolve the case for you but proceed carefully

Enter the cMs and get probable relationships

This online calculator that gives you the probable relationships is an invaluable aid


The DNA Adoption has much help, with a match that close contact is your next step ... review their advice here:

With less close DNA matches, the basic methodology to resolve unknown parentage involves analyzing and building the trees of your best matches ...

Look through the family trees of 2nd, 3rd, and 4th cousin DNA matches for common ancestral couples.

Build private, unsearchable family trees down from each common couple to find where they intersect and produce someone in the right place at the right time.

This may only get to the grandparents  or great grandparents

Clustering can be a quick shortcut to finding the common ancestors. The idea is to display your matches who match each other in an easy to understand visual format

You can sign up to cluster at or you can use the clustering tools from or GEDmatch or MyHeritage or DNA2tree

The result might look like this, each colored box is expected to consist of matches descended from one set of your great grandparents

On some versions of clustering, all the names are clickable to the match (others have a list below)

Here is the cluster image for Jack who was looking for his unknown Dad

The top two boxes were each paternal and the top one was almost all one surname

The clustering methodology was developed by Dana Leeds who has much advice on her site -

There was an unusual surname several times in the 2nd cluster so I used the search box in the large tree for that name and found one couple in recent times where surname 1 married surname 2.

They had 2 sons, one was in the right place at the right time!

A 2nd cousin range match from the first cluster had a huge tree

Since that clustered case was resolved, Genetic Affairs has added a tree building feature. These are the trees it made for the top 2 boxes



Once you have a candidate parent build their pedigree tree back to at least 1800

Make sure this tree is private and unsearchable initially but once you are ready to try it out, you make it searchable so that ThruLines can use it for you

Add a fake child to that parent and then connect your DNA to that fake person

Ancestry will use auto complete in the name field

Select the pedigree tree you created and link your DNA test to the fake child

Now wait ... it often only takes a day to get common ancestor hints ... see if they are consistent with your hypothesis

Click on each Common ancestor in your match page to view the relationship. Consistent with your theory?

Check the cMs of each match and compare them to the charts

Do they fit your theory?

Is there a faster way to check them?

Using the Genetic Affairs tree building feature might be a faster way to have a look to see if the centimorgan amounts fit

Or you can use the "What Are The Odds" tool at DNApainter to check your theory - 

Is there automation for comparing trees

to find common ancestral couples?

Or for building trees?

Collects and compares the trees of your matches into your own private database at



Finds the common ancestors from your Ancestry matches and builds trees!

DNA2tree is only on iPhones and iPads via a paid subscription but it is a real game changer for unknown parentage searches

clicking on Load Some Matches gets these options

Favorites = starred

Next you Find Common Ancestors

Here is a sample set of Common Ancestors 

Note the repeating usernames (privatized) 

See what happens when you Merge Common Ancestors

Now there are only three lines, with no duplication of user names

Details of the Molica matches

Click on Graph to see an image

like this

for the

Molica matches


The DNA matches Brenda and June are 3rd cousins


GGrand parents

Grand parents

Details of the Mollica matches

Click on Build


DNA2tree asks you what to call the tree and then builds that tree on your account at Ancestry


Molica tree  Ancestry built by DNA2tree

For this to work well, you need many matches with good trees

In order to use the tree gatherer you need to be a paid member

GWORKS is available at

download it by clicking here

Find the app called DNAgedcom Client on your computer or look for this icon

Once you are logged in to your account at DNAgedcom you will see this screen

Every person you are working on needs their own account at DNAgedcom but you can use your one paid account to collect the data
Use the GWorks Client (DGC) to gather your Ancestry match data

Enter your ancestry username and password

Once you are logged in, the name(s) of people who have shared DNA with you show up in the profile box, select the desired one in the dropdown

Then choose the cM range, start at 20 for the 4th cousins or better

check the box for gather trees and click Gather DNA Data

WARNING... this gather can take 24 hours, run it overnight!

Now your database is ready!

For adoption cases, I usually start by looking for common ancestors born after 1800

by putting 18 in the box at the top of the Birth Date column and clicking StartsWith

Another useful search is to look for a surname, since spelling varies I often start with the first 3 or 4 letters

Click the arrow next to the name so it points down and all the matches who have this person in their tree will show

Having the same ancestor in 3 or 4 trees may not be significant if the trees are all from the same user

You can use the "Show Trees " on the Gworks page to delete all but one and then rerun the matching

Jane had a third cousin match at Ancestry with a good tree

Can  GWorks can identify which line from the second cousin match is the one they are related on?

Top ten ancestors in GWorks

Can you find any GWorks listed names in the far right of the pedigree?

The Pratt Cranford marriage has 8 children

Three of them have DNA tested descendants, check the abbreviated McGuire diagram for clues

3 children


Surname frequency can help you decide which children's trees to build down in an unknown parentage case

So the next step was to look for the surname of Pratt B's wife and then for child D's spouse

Targeted Testing

Child D's spouse's surname is in the database many times, now to get a child of D, a possible parent to test

These are the names of the original Spanish settlers of New Mexico
These numbers for the tree matches scream out ENDOGAMY

Top ancestors for an unknown father case ...

People with endogamous roots do best to wait for close matches, 2nd cousins (or better) ... Tessa had three, one at each site. She also had been told a surname for the father: PADILLA

23andme match

The 23andme match was the grandchild of (Jose) Pasqual Padilla, sharing 5.1%  or 368 cMs.


Based on other matches the 23andme match was confident that he was the half 1st cousin of the Padilla father we were looking for; that Tessa was descended from the 2nd wife of Pasqual,

thus a half first cousin once removed -1C1R 

The Ancestry and MyHeritage matches shared common ancestors: surname MARTINEZ

23andme match

The Ancestry match - 287 cM - had a tree with just parents. Building that tree in our research tree we found the great grandparents of the My Heritage match -282 cM

Eugenio and Maria Martinez

but they were the great great grandparents of the Ancestry match. The son of that couple who was the Ancestry match's grandad had several wives and many children - so perhaps another  half 1st1R?

Obituaries are a great source for finding the names and parents of the living. This one from the Albuquerque Journal found the Martinez-Padilla marriage we were looking for

Next task was to see if we could find a daughter of (Jose) Trinidad Martinez married to a son of (Jose) Pasqual Padilla

So did Pasqual have a son named Luis?

23andme match
Ancestry match
9 Sons

Yes Pasqual's son Luis married Teresa Martinez! the daughter of (Jose) Trinidad Martinez

Now which of those 9 sons was in California at the right time?

Only 2 of them 

Meanwhile Julie, a daughter of one of the possible half brothers, tested independantly at 23andme and shared 774cM (about 10%)

with Tessa

Now Tessa showed off her sleuthing skills, she called the librarian of the small town that most of these Padillas were from and got copies of their obituaries and lots of information. Neither possible father was still alive but she tracked down a son of each one of them and talked them into testing

So Julie is either a half niece or a 1C1R

image from Blaine Bettinger's chart 2017

Here are the tests results for her possible half  brothers

Tessa was welcomed into her father's family; here she is with her half brother and half niece

French Canadian!

Another example of endogamy, recognize this one?

You can use a parent, half sibling or first cousin match to isolate one side by starring those matches in common

The Genetic Affairs clustering tool lets you cluster JUST YOUR STARRED MATCHES

(as does DNA2tree by collecting only those)

DNAgedcom's client, MyHeritage, DNA2tree and GEDmatch all have clustering too

The profile CSV file from Genetic Affairs clustering can be used for tracking your work

But so is the DNAgedcom m_ file a useful spreadsheet for tracking your research

You can upload GEDcoms from other sources and add them to your database at DNAgedcom


be sure to "Match Gedcom files" again after uploading these on the GWorks Manage Tree FIles page

On the View Trees page you can delete any tree by clicking the red X

The source will be blank when it is an uploaded tree

This blog post explains how to make GEDcom files from online trees via various tools

To learn more take a class at

2. Are there any close matches (1st cousins or closer), figure it out from there

3. Does the genetic affairs clustering and tree builder solve this?

4. If you have DNA2tree, use it to find common ancestors and build a research tree or two

   5. Still puzzled? Run GWorks on DNAgedcom and add trees collected elsewhere

6. Once you have some common ancestors, build those trees down to the present looking for someone in the right place at the right time


1. Use the "Are your parents related" (AYPR) tool at GEDmatch on the adoptee

Unknown Parentage Searches - Sept 2019

By Kitty Cooper

Unknown Parentage Searches - Sept 2019

Using GWorks and other tools for adoption searches

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