Why Are My Y-DNA Surnames Different Than Mine?

When my father submitted his DNA, he submitted an Autosomal test to Ancestry.com and a Y-DNA test to FamilytreeDNA.com.  The Autosomal testing would help us identify more recent relatives (within the past 5-8 generations), and Y-DNA would help us identify the origin of our surname.  When the Y-DNA results came in, my father’s matches were men with the surname O’Byrne, Byrne, Burns, etc.

The results were confusing to us so we joined the O’Byrne  Surname Project on FTDNA.  The project researchers study the male DNA to determine the origin.  Here is what we learned:

Thank you for notifying me of Jerry’s Z255  pack result.  His confirmed Haplogroup as you said is A5411. I did mention that I thought he might be Z16950. He is positive for it as it is above A5411. Looking at his matches at 67 a few of his closer matches were Z16950 which is why I predicted this one. Great to see that he is A5411. On our SNP chart I will now move Jerry from the Z255 group and into Lineage 1e.  You can see from the chart that that A5411 is the ancestor a large group of six lineages 1e to 1j and is dated as 1250 AD. I think this confirms Jerry’s O’Byrne Clan of Leinster ancestry.

Fortunately, the project managers are very skilled researchers.  We gained much infomation about our origin from them.  We descend from the O’Byrne Clan out of Leinster, Ireland dating back to 1250 AD.

Our Autosomal results were interesting.  We had matches to cousins on many sides, but none to the Cubbison lineage.  I looked for O’Byrne cousins and was not able to find any.   This became the beginning of a two year research project. I had to trace my father’s genetic past from the DNA results instead of the family tree paper trail.  I discovered a non-paternal event in the 1870’s in my father’s line.  My great-grandfather descended from a male neighbor.  My research timeline.