Match at Lower Level but Not Higher

[JoeDublin]

Hello,

After years of research and circumstantial evidence, I pinpointed what I believed to be the ancestral location in Ireland for my family. I found a man with the same name in the area who agreed to take the Y-DNA test. As the results came back, we matched exactly at 12 markers. We also match together about 90% of our other matches with different surnames. I was shocked this morning to find that we do not match at all at 25 or 37 markers. Does this mean that we are not related at all? Am I missing something?

Thank you very much for your help.

[tomcat]

Many 12 marker matches go unconfirmed by more extensive testing. The 12 marker is of limited value as evidenced by your matching, at 12 markers, many with other surnames.

Sorry all your work has gone unrewarded. Don't give up!

[sjadelson]

An illustration of Tomcat's point:

I have 370 Y12 matches, 180 of which are GD0. At Y37, only 21 are GD2 or closer, just 6 are GD0. True, not all of my Y12 matches have tested up to Y37, but it shows you how many fall off when you test more markers.

But, keep searching. I have a GD0 up to Y67, the highest level he's tested, which is from a recent branch who made the trip from Lithuania to Ukraine!

[josh w.]

Hello,

After years of research and circumstantial evidence, I pinpointed what I believed to be the ancestral location in Ireland for my family. I found a man with the same name in the area who agreed to take the Y-DNA test. As the results came back, we matched exactly at 12 markers. We also match together about 90% of our other matches with different surnames. I was shocked this morning to find that we do not match at all at 25 or 37 markers. Does this mean that we are not related at all? Am I missing something?

Thank you very much for your help.

This is not unusual. I had a 12 marker match with family from my dad's home town in Lithuania---there is evidence that the respective families actually knew each other. However at 25 markers the relationship was more distant---the lines probably separated before the families ever migrated to Lithuania.