DNA on 1800 ancestor

Question

This has likely been answered, but I cannot find an answer in G2G search.

I just did a "Relationship to Me" search, and found a relationship.  This individual had DNA confirmation of parents (yellow letters) attached to a profile for an individual born in the 1840s, died 1920s.  I do not understand how this can be proven. So, I looked at this:

"Confirmed with DNA" is a Relationship Status level. Using it means this icon will appear by fathers and mothers on profiles and most tree views: 

This indicator should only be used when two or more people have taken DNA tests for genealogy and their results have been carefully compared using one of the methods described on the DNA Confirmation page or using a comparable method that you'd like to discuss adding to this page.

I know that DNA can be extracted from very ancient specimens, but I think it is too expensive to do for genealogy. So, do only two people in the current living generation need to have DNA tests to confirm that great grandparents are proven by DNA?  If that is the case, I need to make some changes because we have tested 3 generations, 5 individuals and added that information to our profiles, but have not added the DNA Confirmation icon.

Comments

Occasionally someone does mistakenly add a DNA test to the profile of a deceased ancestor. See this category. But that's not the situation you describe.

Answer 1

DNA confirmation can also be done via triangulation for more distant relationships. Basically, triangulation is where 3 or more people share a sufficiently long segment of DNA and they each trace their ancestry back to a common ancestor couple.

There are links to autosomal DNA triangulation articles on this page:

http://isogg.org/wiki/Triangulation

Comments

NB. while it is true that 'triangulation' as the word is used at WikiTree does require three descendants who share a MRCA (where two of them might have a lower MRCA but still a GD > 1), the same word is used by others to mean two persons sharing a MRCA.  In the latter case, the three points of the triangle are the two test takers and the MRCA.

I could offer the use of the word 'pyramidization' to explain the WikiTree concept, but it would be unacceptable to the polysyllabically challenged so we will just have to live with the

Answer 2

You may want to review this wiki page:  https://www.wikitree.com/wiki/DNA_Confirmation

For the standards WikiTree uses for marking a relationship "Confirmed with DNA".

In general, if a DNA test between two living individuals indicates they are 3rd cousins or closer, and you also have a traditional genealogy trail indicating that they are 3rd cousins or closer, then you can mark the entire relationship chain as "Confirmed with DNA".  For example, I have a DNA second cousin predicted match on 23andMe with someone who is actually my second cousin once removed, and I also know the genealogy of all the individuals involved.  So I have marked my relationship to my mother as DNA confirmed, along with her to her mother, and on up to the great-great grandparents - even though my great-great grandparents have not been tested.

Beyond 3rd cousins, you need to use triangulation for confirmation, as the DNA trails get a bit sparse.  I have several matches with a single distant cousin that I'm still looking for additional matches to complete the triangulation - I haven't marked any profile relationships as Confirmed with DNA yet, and should not until I have a full triangulation group.

Comments

Thank you both.

Answer 3

Are there wikitree DNA mentors? If not it would be a wonderful addition! I for one could use a mentor to help me processing the highly specific DNA language. Having a brain injury I'm challenged and after a few minutes the information feels like a foreign language. I've had the autosomal and MtDNA full sequence. My mothers brother has taken the autosomal and Y-37.  My sons have taken the autosomal and my fathers Y-111 and autosomal results are pending.

Comments

Hi Cynthia, I'd be glad to work with you if you'd like some help with DNA basics. I can see that there are profiles for several of your mother's siblings, but I don't see that you've posted anything about your mother's brother's DNA tests. That would be the first place to start. Is there a profile on WikiTree for your uncle? Do you understand how to add information about his two DNA tests to his profile? If you like, you can send me a Private Message to discuss your next steps.