My Unexpected DNA Discovery – Part Two

DNA Discovery

Still believing that the journey I was traveling was all about John Costello, I tested myself and my mom.  The results came back and John’s ethnicity was there – loud and proud.  My mom showed 25% European Jewish and I showed 10%.

The surprise of it all hadn’t worn off one bit.  I spent time trying to think through how this had been kept such a secret.  Did it start with John or generations before?  I was hungry to understand John’s motivations and more about his past.

My next steps were all about John.  I poured over mine and my mom’s match lists.  My mom’s brother and mother had both previously tested with Ancestry so I used all four of our results to isolate matches that had to be on John’s line.  I was creating quite a list of Jewish cousins.  Many were willing to help, but their own trees stopped so recently, they didn’t know what to tell me.

My hunger for answers propelled me to learn more about DNA and my options.  Among other things, I learned about autosomal transfers.  I downloaded mine and my mom’s raw data from Ancestry and uploaded it to My Heritage.  We had just a few matches.  Nothing too exciting.  A few weeks later I uploaded our raw data again – this time to FamilyTree DNA.

It was a busy week.  I uploaded the data and forgot all about it for several days.  The following Sunday evening, something reminded me to login and see our results.  I started with my mom’s results.  Those results shocked me even more than learning my Roman Catholic, Spanish-Italian great grandpa was Jewish.  There really is no preparing for something like this.

These are my mom’s top three matches.


Mom's DNA results


I am her closest match and correctly identified as her Parent/Child.

And then there was Bob*.

A name I had stared at so many times.  That only perfect Y-DNA match to my uncle.  Here he was again matching my mom as a possible – Half Sibling, Grandparent/Grandchild, Uncle/Nephew.


{Insert loooooong pause here.}


After swallowing a few times and opening my mouth to say something but then unable to speak, my eyes drifted down to match number three.

My grandmother’s first cousin was the next closest match to my mom.  I knew exactly who that match was by her name.  She is my grandma’s first cousin – that’s really closely related.  I have pictures of her.  Lots of pictures.  I have spoken to her on the phone about family stories.  This woman, this very familiar woman, was my mom’s next closest match.

My eyes just kept going back and forth between the numbers 1,652 and 465.  Those numbers represent the number of centimorgans my mom shares with Bob and with grandma’s cousin.  That first cousin of my grandma – that very familiar woman – matched my mom on 465 centimorgans.  Bob, a complete stranger to me, matched my mom at more than three and a half times the number of centimorgans.  That little bit of math, plus the words Half Sibling, Grandparent/Grandchild, Uncle/Nephew put me at a loss for words.

Once I could think again, I emailed my friend Deborah.  You may know her as the Genealogy Lady.  I sent her a few screenshots to show mine and my mom’s matches and just asked if she had any advice before I took my first step.  Her wise advice was to remind me that being at least one generation removed, I might be in an ideal position to help my family navigate these uncharted waters.  She then gave me the only reasonable suggestion – email Bob, start the conversation.

That night was Father’s Day.  I called my dad with no plans to mention Bob.  But as I spoke with my parents on speaker, eventually I just couldn’t keep it inside.  I told my mom.  She wanted to know what it meant.  What were the possibilities – every conceivable way Bob could fit into our family.

Based on Bob’s perfect Y-DNA match to my uncle, and how he matched my mom and myself, Bob is definitely the son of one of four men.  Bob’s biological father is either:

  • My great grandfather John Costello
  • My grandfather, John’s son
  • One of my two uncles, my mom’s brothers and grandsons of John Costello

That’s it.  No one else is the possible father.

If only I knew Bob’s age.  That crucial number would help whittle down the already short list in a hurry.

I got off the phone, took a deep breath, and decided I would email Bob in the morning.  After I slept on it.  I was about to rock someone’s world.  I wanted to be ready.

I got up the next morning and sent Bob an email.

What do you say to a previously unknown, very close, surprise family member?  Well, I’m not sure what someone else might say, but this is what I said:

Hello Bob,

I recently did a Y-DNA test on my mom’s brother to help solve a genealogy brick wall.  You were his only match of a genetic distance of 0, but you didn’t have a tree so I didn’t contact you.

Last week I uploaded my mom’s and my raw Ancestry DNA data to Family Tree DNA.  Last night I checked her matches and was completely surprised that you are listed as her closest match after me.  It says you could possibly be related to her in one of these ways: Half Siblings, Grandparent/Grandchild, Uncle/Nephew.

On my match list you show up as being my possible: 1st cousin, Uncle/Nephew.

My first question is, are you looking for your father?  If so, I could definitely help you with that.  There are very few possible candidates.

All the Best,



And then I sat back and waited.



Not patiently.




to be continued…


*Names, dates, and places in this series of posts will be changed or omitted for privacy purposes.  You can read the first post in this series here.



26 thoughts on “My Unexpected DNA Discovery – Part Two”

  1. Argghh—I want to know now! 🙂 What a story. When it was just a Y DNA match, I didn’t think you’d get too far; I have a few 0 matches for my brother, but have never found a connection with any of them. But now with the autosomal match—wow! I can’t wait to see what Bob said.

  2. I really do not have much to say except I am a very interested reader. Having a few surprises in my own family history I have a very small idea of what you are going through. Who knew family history could be so…..surprising?

    1. Thank you Cathy! All done with the story by Friday, one wrap up, what to do if you are in the same boat post on Monday. For some weird reason, your comment didn’t show up in my notifications, glad I noticed it anyway. 😉

  3. I love this. I’m away from home working on my old iPad and I just scrolled through all the other posts in my reader to get to yours. If I wasn’t so utterly enthralled ( and frankly impressed by your story-telling abilities) I’d be disappointed not to have resolution. But I do love a good mystery!!

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