Dna ancestors

Question

If you are a DNA match to your 7th great grandfather and grandmother, and research confirms this, why am I (or my mom and cousin) not a DNA match on the profile.  My mom and my first cousin once removed are both 0.39% on the 6th great grandparents.

Answer 1

Autosomal DNA does not post that far out on the ancestors. Autosomal can only be reliable to about the 5th generation - sometimes to the 6th generation but not with a great amount of reliability. So, here on WikiTree the autosomal does not get posted to the 7th set of ancestors.

I am sure someone who can explain better will see your question and answer with more clarity.

Comments

This is not actually true; there is a lower chance of having a match at the distance of 5th or 6th cousin, but that doesn't mean that a match at that distance of relationship is impossible, or that such a match (given sufficient segment length) is "unreliable". My own most-distant DNA-confirmed relationships are in the range of 7th/8th cousin. The chances of having a match at that distance are around 1%, or so, but those ancestors also have thousands of descendants. I can provide numerous examples of my own DNA matches with other Wikitreers, to illustrate my point.

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Yes, I agree with what you are saying but I was just trying to point out that autosomal does not consistently reach that far back for everyone. I have a 3x great that I did not get the right piece of DNA in order to triangulate. I was able to use the DNA of my aunt who did have the right amount of DNA. On other ancestors, I have matches with more DNA farther back. I did not state it very well but those are the reasons our DNA testing is not posted back as far as Susan was asking about.

Answer 2

Autosomal DNA is only noted through six generations because the amount of DNA you would share with ancestors farther back is so small.  The percentages shown here in Wikitree are probably not what you actually share with an ancestor. Here’s the link to the Help page for more information:  https://www.wikitree.com/wiki/Help:DNA_Test_Connections

Comments

Ok, this makes sense. Im trying to learn to use DNA Painter to try to confirm the parentage of my third great grandfather and beyond. Im using known DNA connections for practice. My third great grandfather had two known siblings, who I have found 3rd great grandchildren for who have taken DNA tests.  Im trying to get them to come to Wikitree.