Last year, I was approached online through my Gedmatch account by two people who I share DNA with. Both of them have roots in Cavan. I have no Cavan roots that I am aware of.
Last week, I saw a new match on Gedmatch. It was at 3.7 generations. In DNA terms, that is pretty good, it means we probably share 2nd great grandparents. I shot off an email to the woman and yesterday she responded. She shares my 2nd great grandparent with me. They are my County Laois family, the O'Çonnells, Tallants, and Morans. This is the part of my family I thought most likely came from Cavan since Laois is a lot closer to Cavan than Kerry.
To prove this, I did a one to one kit test on Gedmatch between both of the people who are related to me. They are not related to each other and the chromosome on which our matching DNA is located is not the same either.
That blew that theory all to heck but it did show me that I might be able to isolate the chromosome for certain names in my genealogy. I will be working on this for the immediate future. If I come to any conclusions, I will let you know.
In the mean time, I am again realizing that things are often not the way you would think they should be in genealogy and making assumptions is never a wise thing to do.