DNA testing & reasons to do it

This topic has 10 replies, 8 voices, and was last updated 3 years, 11 months ago by BrennanJMD.

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     Web Editor

    I’ve had some really interesting success with autosomal DNA testing. Have found a couple of close matches – 2nd/3rd cousins, and also solved an old family mystery. The records aren’t always there to back up the science though. Some people in Australia matched me and my aunt, our best guess is a shared set of gggg grandparents, but short of a time machine to check the 1851 census, we probably won’t find the paper connection.

    I’ve also tested a cousin to try and help locate his half-sister, who I discovered by accident when ordering what I thought was someone else’s birth cert. We’ve put his DNA into several of the companies, and Gedmatch, the third party site. It’s a long shot – his sister was born in 1937, before legal adoption, and might even be dead, but we have to try and find her. The good thing about DNA is that he’ll match her descendants too, so maybe we’ll get a hit in a few years.

     Paul Gorry

    I’ve had little (really no) success with yDNA testing.  I have one match with my surname (a person I know and who tested at my suggestion).  Otherwise the matches are with random surnames.  I had hoped to find that my people were a branch of a more common Irish line (like O’Neill, O’Connor or the likes).  There is no pattern to the names that matched.

    Autosomal was altogether different.  We got a few strategically placed family members to test so that we could determine on which side of the family a match most likely connected.  We made contact with a descendant of my great-granduncle, of whom I had no record till the match.  The relevant parish register starts far too late, but other records provided the evidence that this man was indeed my great-grandmother’s brother.

    Then there was a match with someone who had my great-great-grandparents as their ancestors.  They were descended from a daughter named Julia and I had no record of her.  True enough, when I investigated it Julia was indeed a daughter.  Julia’s mother had an extremely rare surname that I’ve been wondering about for years.  The Autosomal matches include two separate people who have that surname in their trees, so Autosomal DNA has opened new vistas for my ancestral research.

     Web Editor

    That’s great success.

    I agree about YDNA though. I tested my uncle and the results are less than useless.

     Kate in PA

    The best thing I ever did was pay for my aunts – one on each side – to get tested. Unfortunately, my parents are deceased, so my aunts are the next best thing. It’s not the perfect solution, but I’ve been able to separate the two sides of my family to an extraordinary degree by seeing if people share DNA with one of my aunts. I’ve been very fortunate with DNA matches. One brief example: my g-g-grandfather left Tipperary with his four brothers in 1849 and they all settled in the St. Lawrence River region of Ontario. We knew there were three additional siblings and since no one had ever heard a word about their families, we assumed the three siblings stayed in Ireland. Then we had our DNA tested and found descendants of all three!  A brother had settled in upstate New York; a sister in Chicago; and another sister in San Francisco by way of Australia. We also managed to prove that our family was indeed part of a very well-known clan in Tipperary – one that traces its origins back centuries. So, it has been a boon to us. (By us, I mean a group of cousins who are all amateur genealogists.) I had my cousin’s y-DNA tested and found it to be not very valuable. I was able to nail down an approximate county of origin, but that is it. I’ve found no real connections with y-DNA.


    I would be interested in having a DNA test but its difficult to know which company is the best one for genealogy research. Any advise would be appreciated.


    Butterfly, From what I have read for genealogical purposes the autosomal test from Ancestry would be one of the best simply because they have around four million subscribers. You can then upload the results to Gedmatch (free) at https://gedmatch.com/   for further analysis. Geoff


     Web Editor

    Ancestry does have the most people in their database but they are mostly American. If you are Irish and looking for Irish links, i.e. people who did not emigrate, then you might be better off with FTDNA.

    Also, many of the sites allow you to upload your results to another site, either for free or for a small fee.

    I tested a cousin with Ancestry but was able to transfer his results to FTDNA for free (though there may have been an offer at the time) and Myheritage (which is less than useless).

     Bob Frewen

    To add to what ClaireB has written –

    Choice of testing company and the type of test depend on what you want to achieve. Do not expect too much. Arguably the best two for genealogy are FTDNA and Ancestry. I have taken tests with both.

    Neither FamilyTree’s 37-marker Y-DNA test (applicable to males only) nor the autosomal test (‘general’) with Ancestry produced much information and the little bit it did has not been of use.

    My Y-DNA tells me that my “Predicted Haplogroup is R-M269” and probably Z253. Great, but M269 is the dominant lineage in all of Western Europe. My 37-marker test produced 2 matches at a genetic distance of 2 and 15 matches at 4. None of them bears either my surname or a name in my (almost 700 member) family tree. Because I have no close matches it is now suggested that I do a 67 marker one to refine the results.

    My Ancestry test produced one ‘find’ – a first cousin once removed that I knew about.  It shows 2 people described as third cousins i.e. we share one of our 16 gggrandparents (statistically I have about 200 third cousins). Neither of them have surnames I recognise, neither has logged on to the Ancestry database in months, nor have they responded to emails.  Also neither of them have uploaded trees, same as most of the other matches.

    It is interesting to look at and learn about the process, but genealogically DNA testing has done nothing for me.


    Hi to all, Thank you for all your contributions. I will think a bit more about whether to go this route, maybe sometime in the future.

    thanks again.


    I have tested with both Ancestry and FTDNA.  I found more of the matches on FTDNA replied to my emails.

    I was pleased that the resulting matches confirmed the paperwork I had done on 3 of my 4 four grandparental lines (the fourth -Murphy from Cork I have postponed doing serious research on).  The DNA matches confirmed the work we had done on an illegitimate daughter of a great aunt, who had been fostered out away from the family.  The matches also  led to contact with the descendants of three of the family who had gone to Chicago in the late 19th century.  It meant that we from Ireland were able to put those Chicago relations back in touch with each other too.

    So to date DNA has served more as a confirmation of existing paper-based genealogy.  However I hope in time it will lead us to my father’s half sibling, born in England somewhere in the late 1920s or early 1930s, of an Irish mother, and my English grandfather William Edward Williams.  Whilst we know my grandfather continued to support the mother and child after he returned to his wife and children in Cork, we do not even know whether the child was a boy or a girl.

    To date we have had nothing useful from the Y-DNA testing done in the family.




    I have no success with yDNA testing. The matches were all with people whose MRCA to me was 8 or 9 generations back which is of no use to someone like me who comes from a long line of RC peasantry from the West of Ireland! My wife and I have enjoyed some success with autosomal DNA testing unearthing several 3rd cousins and were subsequently able to find primary records to supplement the DNA connection.

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