dna, Finding John Costello

Finding John Costello – A DNA Journey: Connecting Four Cousins

Finding John Costello, cfc-01


Finding John Costello is a top priority for me.  He is my great-grandfather.  My mother knew him.  He died when she was eleven.  His three children who survived infancy were all still alive until Uncle Dan passed in 2015.  Despite access to the people who knew him best, and plenty of time asking them questions, John’s pre-marriage life remains a mystery.

It seems DNA may be my only hope in identifying John’s origins.  But John’s two living children, Virginia and Vince, will not take a DNA test.  So far, three of John’s grandchildren have tested and three of his great-grandchildren have tested.  Those six descendants have tested with different companies as seen here:


John Costello & Mary Brown Young Descendancy Chart (1)
Blue squares in the first chart are descendants of John Costello who have taken a DNA test.  The second chart indicates which vendor(s) they have tested with.


I have access to the DNA accounts of Mack*, Uncle C, Debbie – who is my Mom, and of course, my own.  Each of these accounts has brought different pieces of information to the John Costello puzzle.  In an effort to begin connecting our DNA matches, I built a Master Match Tree on Ancestry.com.

For a while, I just kept adding unconnected branches.  I built those branches back, out, and down trying to find connections between my matches.  Those efforts paid off when I struck gold in an obituary.  That obit brought two of my matches together.

Sam* and Isaac*, two of our DNA matches, are 2nd cousins once removed.  Sam is one of our closest DNA matches on John Costello’s side of our tree.  Identifying the MRCA couple for Sam and Isaac felt like a huge step forward in my efforts to find John Costello’s story.


connecting two descendants
Names in blue indicate individuals who have taken a DNA test.


Things got even more exciting when I checked MyHeritage and realized that Sam’s daughter had tested there.


connecting three descendants
Names in blue indicate individuals who have taken a DNA test.


I started comparing the shared cMs between my family members and these three descendants of Isidore Fried & Sarah Esther Salzman.  It was looking like Isidore & Sarah were fairly close relatives of John Costello.  In fact, the relationship that just started thrumming through my head was aunt/uncle.  It was so loud that I charted out the connections based on that relationship and then checked all of the shared cMs.  It worked!

I knew that wasn’t enough information, and there were likely some other possibilities, but seeing that set of relationships sketched out with numbers that worked, heightened the importance of this cluster to my research.

I hopped on over to 23&Me and I found another descendant of Isidore & Sarah who had tested there and matched Mary and myself.


connecting four descendants
Names in blue indicate individuals who have taken a DNA test.


Oooooh, this was getting good!!  I now had four descendants of Isidore and Sarah who had tested and six descendants of John Costello who had tested.  Now it was time to chart out some possible relationships between Isidore & Sarah and John Costello.

Using the Shared cM tool on DNA painter to give me some ideas on relationship theories to test, I made some charts.

The first theory I tested was that Isidore or Sarah was the aunt/uncle of John Costello.  I created a relationship chart based on that theory:


aunt:uncle relationships chart
Names in blue indicate individuals who have taken a DNA test.  Please note that Jim has been left out of these charts as I don’t have access to his results.  He does, however, show up in the list of shared matches.



Next, I created a chart of the shared cMs between these matches and ran the numbers through the Shared cM tool on DNA Painter to see if the charted relationships were possible.  These are the results:


theory 1 - aunt:uncle cMs chart
Names in blue indicate individuals who have taken a DNA test.


Theory 1, that Isidore or Sarah was the aunt/uncle of John Costello, is possible.


I followed these same steps for five additional theories:

Theory 2 – that Isidore or Sarah was the half-sibling of John Costello.

Theory 3 – that Isidore or Sarah was the sibling of John Costello.

Theory 4 – that Isidore or Sarah was the 1C of John Costello.

Theory 5 – that Isidore or Sarah was the half-aunt/uncle of John Costello.

Theory 6 – that Isidore or Sarah was the 1C1R of John Costello.


Of those six theories, three work and three do not.

Isidore Fried & Sarah Esther Salzman appear to be related to John Costello in one of three ways – as his aunt/uncle, half-sibling, or sibling.




I have a MRCA couple to research!!


Isidore Fried & Sarah Esther Salzman are very important to the John Costello story.  I need to learn everything about them that I can.  These efforts will have two prongs – traditional research, and more DNA tests.

For the traditional research side of things, I have some interesting data so far.  I know that the couple’s oldest daughter, Leona, used the birthdate of 4 July 1903.  On various records, her birthplace is listed as Russia; Ukraine; Kiev, Ukraine, and Kyiv.  The other children of Isidore & Sarah were born in the US.  I have a lot of information to work with and I’m hoping that I can develop my tree further and learn about the origins of Isidore, Sarah, and Leona.  Learning their story just might lead me to John Costello.

For the DNA side of my research, I want to test several people.  In my own family, I want to test Vince and Virginia.  Assuming they never agree to do so, I want to test each of John Costello’s grandchildren.  I’m interested in testing them at Ancestry and 23&Me.  I would also like to test Suzanna*, Sam’s* mother.  She has twice the genetic data of her ancestors than what she passed on to Sam.  Adding those additional tests may help refine the relationship possibilities further.


I am so excited about this progress!



Descendants of Isidore Fried & Sarah Esther Salzman, if you come across this post, I would love to hear from you!  My email address is on the sidebar.   ❤️



Happy Friday, I hope it’s a weekend filled to the brim with genealogy discovery for you!!  xoxo



*All names of living individuals have been changed unless that person gave me permission to use their name.