Are there enough DNA tests to show relationships as DNA-Confirmed?

+10 votes
198 views

Four profiles have autosomal matches using Gedmatch. Elnathan Griffin is the common ancestor.

All four have good paper trails as descendants of Elnathan.

Jack is a descendant of Abigail, daughter of Elnathan.

Aimee, Jason and Philip are descendants of Aaron, son of Elnathan.

Jack & Philip are 5th cousins 2 times removed. 34.0 cm.DNA segments.

Aimee and Philip are 4th cousins 2 times removed. 10.8 cm DNA segments.

Jason and Philip are 3rd cousins 2 times removed. 40.2. cM DNA segments.

Can I mark the descendant lines as confirmed by DNA?  I have read the material on Autosomal Triangulation 

Jack, Jason and Philip share a common 11.5 cM segment on chromosome 14 from 58,327,312 to 71,975,528.

Aimee has common DNA with Philip, they are 4th cousins 2 times removed, but not with Jason or Jack.  Aimee and Jason are 6th cousins, Aimee and Jack are 7th cousins.

  

WikiTree profile: Elnathan Griffin
in The Tree House by Philip Smith G2G6 Pilot (270k points)

1 Answer

+3 votes

According to the help

1. You will need at least three test matches (you and two or more distant cousins) who all match on the same segment of DNA to confidently confirm which ancestor(s) you have in common.

2. "Those who all match each other on the same segment form a triangulated group (TG). Using WikiTree's Relationship Finder find the shared ancestral couple for that TG."

Since Jack, Jason, and Philip share a common segment, the guidelines allow Jack, Jason, and Philip to mark "Confirmed with DNA" up to and INCLUDING the common ancestors.

This seems wrong to me.  These are the guidelines used when you don't have a documented tree.  A shared segment could have only come from one of the Most Recent Common Ancestors, not an ancestral couple. When you don't have a tree, you only need to find one in order to focus your research.

I would say that you can defend your claims of parent/child relationships for the connections up to but not including the common ancestors of both...

* Philip and Aimme 4C2R
Philp and Jason 3C2R
Philip and Jack 5C2R

Jason and Jack 3C2R

* "can't confirm with DNA under current rules, no triangulation"

by Ken Sargent G2G6 Mach 5 (56.6k points)

Pictures of successful triangulation between 3 people of different lines that share a set of great great great grandparents.

http://www.wikitree.com/index.php?title=Space:Successful_DNA_Triangulation&public=1

The diagrams are interesting and seem valuable - it is possible to have some instructions on how to create them?  What web site?  What functions?

Thank you.
Hello Ken,

Where does it say "INCLUDING"? What is that url?   You can include the ancestral couple when using the quantitative approach for auDNA matching between 3rd cousins and closer.  This is triangulation and so you don't know for sure which parent (of the ancestral couple) is the contributor.

Thanks and sincerely,

I am not good at this part so I will try my best to explain. I am a visual learner and not good with words.....

First you need to download your raw DNA data from your testing company and then upload it to www.gedmatch.com

It takes a day or 2 for your DNA to be fully in the database but you can compare your DNA 1 to 1 with another person as long as you know their GEDmatch ID (in other words they would already be on GEDmatch). After a day or 2 you can use the "Compare One to Many", just enter your ID (which you will have once you create/upload your raw data).

After you get the list of "Compare One to Many", you can "Select" (click the little box in the Select Row) as many matches as you choose HOWEVER it easier to read and triangulate with only 2 matches selected at a time. Then hit the "Submit" button.

On the next page you can either click the "Traceability" or my favorite the "3D Chrome Browser" to see where and how all three of you match.

Some tips:

Make sure your matches are not siblings, parent and child as they need to be of separate lines that all meet at the most common ancestor. I also find it is helpful to first use the compare 1 to 1 function, first to compare myself against each one of the matches I am hoping to triangulate with, just to make sure we do match as the one to many can read a false positive for a match. Once I know I match both of them, I also use the 1 to 1 and compare them to each other.

Peter, please reread #2.  According to this guideline.

"find the shared ancestral couple for that TG."

An "Ancestral Couple" is two people who,according to these giudelines,are determined once you find a single TG.  According to these guidelines, you found the Ancestral Couple, and there is nothing to indicate that you wouldn't include this Ancestral Couple in the confirmation.

You can determine which parent is the contributor, but only when one of the matches is "more distant."

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