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.


25 thoughts on “Finding John Costello – A DNA Journey: Connecting Four Cousins”

  1. We need (or is there) a tool similar to the What Are the Odds? (WATO) to input the data like you did in the final chart. Mack appears to share a much higher amount with Isaac than Debbie and Uncle C. share with Isaac. Also Mack’s daughter Mary shares a higher amount with Bernard than you do. It seems like Virginia inherited more of John’s DNA than Vince did when looking at the cMs shared with the Fried-Salzman couple’s descendants. I hope my observations don’t confuse you.

    1. I don’t know if there is a tool like that…?

      Yes, I observed those things as well. It is a really great illustration of why we need to use targeted testing. In my case, the ideal would be to test Vince and Virginia and all of Dan’s kids. That is the closest I can get to John. Without Vince and Virginia, all of the grandchildren become so important to getting as many genetic pieces of John as I can.

      The number I find most interesting is Mary’s shared cMs with Bernard. Aside from Mack’s shared cMs to Sam, it’s the highest number of shared cMs in our family to the Fried-Salzman family and Mary is a great-grandchild of John. !! Every family member brings a piece of the DNA puzzle to the table – that is for sure.

      1. I didn’t want to put a damper on your excitement and refrained from commenting on the possibility of the MRCA being perhaps a bit more distant than the cMs suggest due to your mother’s 25% Jewish ethnicity result which you say comes from John.

        1. Yes, I know endogamy is a factor in this situation… But I don’t know how to quantify it, so for now, it’s just something I’m keeping in mind. But the good news is that despite endogamy potentially playing a role, I do have a good cluster of DNA matches that have a MRCA in Isidore and Sarah. It offers more hope than I’ve ever been able to get from the records from John’s life. Now I just have to learn all about them and watch for a good candidate for my John. (It seems very likely that his name at birth won’t be John Costello – but who knows?) Now I need to learn more about using DNA Painter and start analyzing the segment data…

    2. Oh my word, Cathy! I just realized that I left out my surprise 1st cousin from the figures here. I need to add his numbers to the mix!! (He’s not on Ancestry but he is on 23&Me.)

  2. This is all very exciting, and I am trying to focus on it, but my head is still in a bit of a fog. I am trying to read the charts to see how much DNA is shared between your Costello relatives and these matches, but it is eluding me. I agree with Cathy—Jewish matches are ordinarily much more distant than they appear—the opposite of what happens in the sideview mirror…

    1. Oh, Amy, I am so sorry for your loss. I imagine you will feel foggy for a while. You are in my thoughts and I hope that you have been able to recall wonderful memories to bring some comfort.

      Yes, you and Cathy both bring up an important point about endogamy. The problem is that I don’t know how to quantify it. So, for now, I’m just trying to keep very good track of how my matches match each other and know that the generation in which they connect to us is likely further back. Right now I don’t have many of us in places where segment data can be analyzed. I’m working on that next. But I’m so excited to have a cluster of matches to research! It’s a much bigger step than I’ve been able to take based on the records of John’s life. Progress feels good. ❤️

      1. I didn’t mean to diminish your discoveries—just sharing my own frustration with DNA. But you are much more expert than I am at doing this. My real question was how much DNA do John’s grandchildren actually share with these cousins and what are the largest segments like?

        Thanks for your thoughts, Amberly. I am trying to start getting back into my “regular” life.

        1. Oh, I know you didn’t! I get it for sure. Good question. Only a few of us are on 23&Me or MyHeritage but here is the segment data for some of the relationships:

          Bernard and I share 66 cMs over 3 segments. Bernard and Mary share 159 cMs over 4 segments. Bernard and my surprise 1st cousin (who I forgot to include in my charts) share 63 cMs over 4 segments.

          Faith and my Mom share 54.5 cMs over 4 segments. Faith and my Uncle C share 54.5 cMs over 5 segments.

            1. They are pretty significant. I’m hoping to get more data by testing more people at more places. I’m making progress! 🙂

  3. Hi Amberly.

    I’m catching up on posts I have missed – DNA matches can be such a maze to wade through sometimes, especially so when you have this unknown branch. However, you are approaching this in just the right way – being methodical and measured.
    I don’t know if you have seen some posts I wrote earlier this year where I have managed to track down two potential names (brothers) to be the elusive father of my maternal grandmother – down to DNA and checking out shared matches etc.

    I don’t know if you have seen but Ancestry are trialling a beta tool called Thru-Lines where it utilises information on trees in their database against DNA matches to try to build up trees to show potential connections with your DNA matches – especially helpful if your matches have private trees, unlinked trees or just trees with very little info on them. Might be worth taking a look (if you haven’t already) Of course always need to be taken with a pinch of salt as of course if someone has done a load of incorrect research it might guide you down a wrong path (garbage in = garbage out.)

    Wishing you much luck in the hunt for John’s origins! Looking forward to further updates!


    1. Hi Alex! It’s good to hear from you. 🙂

      No, I have been pretty MIA on the blog reading this year. Lots of busy stuff for me – mostly good busy, but still, stretched too thin. So, I missed your posts.

      Yes, I have looked through the Thru-Lines. Nothing helpful on the John Costello front but that’s not surprising. He was Jewish so his closest matches don’t have any tree data that connects us or gives us possible connections. I’ve had to do the research to connect my shared matches to each other.

      Thank you for the good wishes! ❤️ One of these days, I’m going to figure this out.

      1. I’ve subscribed by email now so I won’t miss new posts from you (no idea why I didn’t do that before!) Definitely want to see how you go with John Costello. Let’s hope at some point someone takes a DNA test that gives you some good closer matches with something a little more concrete to go on!

        1. Yes! I am hoping for that. Although, this cluster might be about a close I get generationally. I’m hoping to get a few individuals to test who are one generation older but we shall see. 🙂

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