The Basics for Solving Unknown Parentage Cases using DNA
KITTY MUNSON COOPER
These slides can be found at
Why does testing your DNA help?
You get half your DNA from each parent, about a quarter from each grandparent and so forth ....so if enough biological relatives are tested you can figure this out
Step 1: TEST your DNA:
at Ancestry and 23andme then transfer to the other sites
also test any close biological relatives that will help
Step 2: Upload the Ancestry DNA results to other sites for free to get more matches:
- Family Tree DNA *
- LivingDNA (primarily British, not many matches yet)
* pay a little $ to unlock tools
Most 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
The DNA Adoption has much help, with a match that close contact is your next step ... review their advice here: https://dnaadoption.org/first-timers/step-9/
Then read step 10: https://dnaadoption.org/first-timers/step-10/
Enter the cMs and get probable relationships https://dnapainter.com/tools/sharedcmv4
This online calculator that gives you the probable relationships is an invaluable aid
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 ("pedigree triangulation")
Use Ancestry.com to 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
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 or two 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?
Clicking on a person's name in the list of matches takes you to the DNA match page
Does this fit your theory?
Next click on the shared ancestor's name in the left hand column box called "Common Ancestors" to get to this view which shows the relationship
Let's look at how this works with an actual solved case.
Tessa was looking for her unknown father. All she knew his surname was Padilla and that it was an encounter in a town in California in a specific year
It's very helpful when one parent or a half sibling is tested
Because you can separate out the matches and ethnicity of the unknown parent
What does this ethnic mix tell us?
Hispanic, Mexico or New Mexico
People with endogamous roots do best to wait for close matches, 2nd cousins (or better) ... Tessa had three good paternal matches, one at each site.
The surnames of many of the paternal matches looked New Mexican to me (endogamous!)
When I lived in Albuquerque, I learned a great deal about the early Spanish settlers of that area so I was happy to help Tessa find her unknown Dad
The 23andme match was the grandchild of (Jose) Pasqual PADILLA sharing 5.1%
or 368 cMs.
Based on other matches and their ages, the 23andme match was confident that he was the half 1st cousin of the Padilla father we were looking for; that Tessa's grandad was a son of the 2nd wife of Pasqual Padilla,
thus a half first cousin once removed - Half1C1R to Tessa
The Ancestry and MyHeritage matches shared common ancestors: surname MARTINEZ
The Ancestry match - 287 cM - had a tree with just parents. Building that tree in our research tree we found common ancestors with the My Heritage match of 282 cM
Eugenio and Maria Martinez
but they were the great great grandparents of the Ancestry match. Jose, 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 for Trinidad Martinez from the Albuquerque Journal found the Martinez-Padilla pairing 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?
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%)
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 at Ancestry
Tessa was welcomed into her father's family; here she is with her half brother and half niece
To learn more take a class at DNAadoption.com
Or join Cece Moore's FaceBook group for adoptees
Or read my blog
all images either screenshots or used by permission, note that the relationship images are from Blaine Bettinger's chart 2017
Unknown Parentage Searches Part 1: Rootstech Connect 2021
By Kitty Cooper