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Working on my geneology family tree I discovered my 6th generation grandfather link with another person. I had a DNA test and no match came back with the other person who also had DNA test and I have a link to the same person of the family tree.

Is that possible the could be no link between us via DNA and test both still be linked by the same person in the tree? I am a direct descendent and I am not sure if the other person is a direct descendant. I am a male and the other person is a female. The Y-chromosome could be a factor?

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    Downvoted because it is not clear what you're asking. What do you mean that you have a "6th generation grandfather link" with the other person? Please use standard terminology.
    – Jan Murphy ♦
    Jan 28, 2018 at 2:23
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    @Jan My assumption was a shared 6th great grandfather. I put 7th cousin in to clarify the title, but it's really neither here nor there whether the relative is a 7th cousin, 6th cousin, 6th cousin twice removed, etc. Bottom line is the possible link is far back.
    – Harry V. ♦
    Jan 28, 2018 at 2:51
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    @HarryVervet I understand why you made that assumption, but I'd still like to have this clarified.
    – Jan Murphy ♦
    Jan 28, 2018 at 7:08

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The amount of autosomal DNA shared by 6th or 7th cousins is quite small. Some will share no detectable DNA. The latest data of the Shared cM Project shows that seventh cousins share between 0 and 57 cM, with an average of 13 cM.

The Y-DNA plays no role in this. Your female match has two X-chromosomes, and you have an X and a Y, but assuming this cousin is on your paternal side you would not expect to share any X or Y DNA with her.

Autosomal DNA inheritance is quite random at this level, due to the cumulative effect of genetic recombination. The segments you share, if any, might be quite small.

If you upload your DNA to Gedmatch, you can do a One-to-one comparison but lower the thresholds (to say 3 cM) to pick up small segments. Interpreting small shared segments has to be done with caution as you may share these segments by pure chance rather than common ancestry.

DNA is not conclusive with many distant matches. A non-match indicates either no genetic relationship, or distant relationship (likely 6th cousin or more distant). With small segment matches, this means there is either a distant genetic relationship, or matching segments occuring by chance. The DNA can provide you with a hint in this case, but it is up to the genealogist to verify any relationship by DNA testing other potential relatives on this line, as well as scrutinizing the paper-trail to identify any "non-paternal events" or the like. My advice would be to use the DNA as a piece in the puzzle here, but be careful not to over-interpret it.

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