Y-DNA results

[TheBam]

I’ve been using DNA to try and figure out my fathers paternal line as he was illegitimate and finally received the results of my y-DNA test today.

I had a total of 3 matches at the 37 marker, highest had a genetic distance of 2, the other 2 had a distance of 3.
Interestingly though all had the same surname, albeit not all had the same spelling.

Can I now make a reasonable assumption that my GF also shared the same surname?

Using matches based on my autosomal DNA, I had noted this was a common enough surname within their family trees so not a total surprise, although it wasn’t one I expected.

[davidft]

From my personal experience ( I have also tested with FTDNA) the only matches that you can infer much from at 37 markers are where you have a complete match. If you have a genetic distance of 2 or 3 then their tables tell you there is a probability of being related at 8 generations of about 70-80 percent or in other words there is a 20-30 per cent chance you are not related.

Even if your matches have the same or a similar surname to you it does not necessarily mean you are all descended from the same person as some surnames have several different sources.

I originally tested at 37 level and did not make any breakthrough so i upped it to 67 markers and the closest match is at 5 markers distant. I have a reasonably common surname and i know my lineage but my reason for taking the test was to try and take my direct paternal line back beyond 1740. Several years on and still waiting whilst in the meantime i have known people test and get helpful results back really quickly. It is all a bit of a lottery and patience may be required.

If i could give any advise or comment i would say consider upping the test to at least 67 markers and i would not assume you have got the name of your grandfather without more evidence and closer matches. All that said it may still be some time before you can further this and satisfactorily answer your own question.

Hopefully others will also give you their views to help you consider things further.

Good luck

[TheBam]

Thanks for the reply, much appreciated.
I did notice that one of my matches had already tested at 67 markers, if I also upgrade  I guess this will provide me with a more definitive result?