Challenges with Irish Autosomal DNA Genealogy Research

Dr. Maurice Gleeson gave an excellent (and humorous) presentation this last weekend at the i4gg (Institute for Genetic Genealogy) in Chevy Chase, Maryland.


Although his focus is Irish, this information applies to anyone utilizing autosomal DNA.


He has very graciously made his presentation available on YouTube.  Enjoy.




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10 thoughts on “Challenges with Irish Autosomal DNA Genealogy Research

  1. thanks Roberta

    I need to re-see it. or get the PDF.
    My issue is I have broken through the “brick wall” via BDM’s for both paternal and maternal, but I cannot seem to link these people genetically. I do have one triangulation though.

    kind regards

  2. Do you have a link to get the PDF version of the talk? I would like to be able to click on some of the links.

  3. Pingback: DNAeXplain Archives – Basic Education Articles | DNAeXplained – Genetic Genealogy

  4. Was looking through your ‘historical documents’ list and saw this blog again. But this time it was more personal for me. Because I have recently done exactly what was laid out in your goals on this page. I read this blog post and watched the video last year when you posted it. I was trying to improve my knowledge of atDNA and its uses. I didn’t really connect to the Irish part of it because I didn’t know much about any Irish in my ancestry. I have a great great grandmother who was Mary McGrath. She was born in England, but on one census report showed that her parents were born in Ireland.

    Then a bit later I found a marriage registration that showed the name of her father was Edward McGrath. Just a name. A little later I got a copy of the marriage certificate from family members and there were signatures of two witnesses: a Daniel McGrath and a Ward(?) Mooney. A haphazard guess was that it was a brother (later verified) and a friend of the couple (later proven wrong – always check names of witnesses for possible family connections!). I still didn’t have Mary McGrath’s mother’s name. And she was the only great great great grandparent that I didn’t have a name for! I wanted to break down this brick wall!

    I have myself and my parents tested at 23andMe. My mom is not from an endogamous population, so she rarely has matches with more than a segment or two. I invite all of her matches to ‘share genomes.’ In September one of them accepted my invite and said that he also had a great great grandmother that was a McGrath. A Mary Ann also, but not the same one. There were three Edward McGraths also. I wasn’t too concerned because McGrath is a pretty common Irish name and the connection could be somewhere else. But then a few weeks later I noticed that this DNA match had 4 rather large segments matching with my mom. That much DNA can’t travel down the line very far, so it had to be a closer connection than I first thought. And McGrath was the only common name.

    I was determined to explore this some more. So I sent more questions and gave all of the information that I had. Fortunately, the match’s great grandmother had researched and written about the McGrath family many years ago and passed the information to her son, who continued the research. Fortunately the family kept this wonderful research. The information showed an Edward McGrath that was from the mid 1800s that had five children, but none of them was a Mary Ann. At least that’s what the match said. His mother had more detailed information. I then told him about the marriage certificate from Palmer, Massachusetts with his name on it. I threw every scrap of detail that I knew in hopes of making a connection!

    And it finally worked! Palmer, Massachusetts was the key. That’s where his Edward McGrath lived (and died) also. The match checked with his mother and she said that there was a Mary Ann that the match wasn’t aware of and the family’s treasured information had her husband’s name as that of my great great grandfather. So my ancestor married a local man, but they moved away to Louisiana and lost touch with the rest of the family. As I reconnected with this family, they were able to provide me with the name I had been looking for. My great great great grandmother’s name was Maria Ettadosia Mooney. And an interesting name it is.

    I found out that the family moved from Roscommon, Ireland some time between 1838 and 1854, probably some time in the 1840s. This was the time of the Great Potato Famine and Roscommon was central to some of the historic events. I’ve heard about this for years, but never dreamed that my family was in any way personally affected by it. Now I know quite a different story.

    Thanks for the tools that were so helpful in breaking down this wall. You said it could be done. And you were right. Éirinn go Brách

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