Friday, March 24, 2017

Template of My Letter to Triangulation Groups

Triangulation Group # in email header

Good morning Cousins,

According to a segment analysis and triangulation on Gedmatch we share a common set of grandparents or a common grandparent sometime in the past. Collectively we are identified as a triangulation group or TG. Our challenge is to compare our trees and find who our common ancestors are.

My most up to date tree is on Wikitree and is listed as Shoff-7. Please study it closely. I’m showing you mine, will you show me yours?

Wikitree is about collaboration with other genealogists; sharing stories and sources to bring our ancestors together linking them in one worldwide tree that is free of redundancies.

I encourage anyone who is serious about genealogy to upload or build a tree on this dynamically awesome free site. Wikitree has volunteers who are very helpful if you have any challenges. The benefit of its easy access, cousins working together, experts mentoring novices, and interface with Gedmatch tools is unparalleled.

Be sure to include your Gedmatch number on your profile page on WikiTree. In addition to traditional sourcing and documentation, triangulation is fast becoming the most powerful scientific tool to validate or disprove an ancestral link.

DNA does not lie* when used within specific guideline parameters:

1. Three people who are not too closely related share the same ancestor in a sourced documented tree. (sources may include: books, periodicals, newpaper articles, census records, ship logs, birth records, marriage records, land records, wills, court records, bible records, personal knowledge of those who have firsthand knowledge.) You may utilize sources by other researchers from other sites. (Please acknowledge their contribution by insertion of internet url to their site. Such as Rootsweb Worldconnect) Photographs and actual document scans are especially appreciated. (see my up coming blog on easy sourcing)

2. The three people match on the same segment of the same chromosome.

3. The length of the shared segment is 16 cM’s or greater.

(In the future smaller segment sizes may be considered valid evidence. As of April 2017, the 16 cM size is considered as solid evidence.)

This is how we triangulate:

(I insert cropped screen shot here.)Here is a of screenshot from Gedmatch Tier 1 tools showing segment triangulation with contact information of those in this shared triangulation  group. Please, let’s collaborate with each other sharing trees and helping each other find our common ancestor. (You may already have the answer in your tree and, by registering and uploading to Wikitree we may immediately find our common ancestor who links all of us together with yet another cousin who is already using the Wikitree site.

(I insert cropped screen shot here.) Here is a screenshot of my graphic triangulation tree from Tier 1 Gedmatch tools that shows another perspective of how we link. (For those who better understand through visualization.)

Kudos in advance to our cousin who first announces our common ancestors to our TG.

Please use this triangulation group number in emails headers when collaborating with other members of our triangulation group. (TG)

Scientific understanding is not necessary to make triangulation work. This would be like understanding how electricity works in order to have a light. I am simply sharing with you how to locate the switch and turn it on.

Your cousin,

Barbara Shoff
Gedmatch #:  T689325
WikiTree: Shoff-7

P.S. If you decide to contribute to Gedmatch Tier 1 tools and download your own segment and triangulation analysis, feel free to use this letter written by Barbara Shoff as a template for contacting cousins. I used the Paint application for inserted graphics.

If you want to understand the way the electricity works I recommend:  Start with Jim Bartlett’s very first blog.  Your eyes may cross if you haven’t yet read Jim Bartlett’s blog.

*DNA results can be misinterpreted; that is why it is important to use larger segments in triangulation. 


  1. Thank you so much for sharing this letter and encouraging people to post their trees on WikiTree and their DNA results on GedMatch. I am trying to find my 68-year old husband's birth parents and the more info like this that I have, the better my chances. Peg

    1. Peg, I am going to post a PM sheet I send to adoptees. You will also want to join FB group, DNA Detectives. It was started by CeCe Moore to aid adoptees and anyone with brickwalls that need to be knocked down.

  2. You seem like you're pretty conversant with the use of GEDmatch tools. What book, or preferably website would you recommend to getting an understanding of GEDmatch? I find it pretty geeky, and even though I've been staring at it for almost two years, still unapproachable in many ways. As an adoptee looking for triangulating matches, I'd sure hate to see the reaction of a needed first or second cousin match to this website! At least I have a degree in computer network administration under my belt, most people would just glaze over at GEDmatch.

    1. D R Hunter, I am about the least geeky person I know. I too stared at Gedmatch for a couple of years. I began play with people who match on one or both of two kits. Searching the gedcoms and planning on writing the matching Gedmatch number to see if people were in my one to many. Most of them didin't have Gedmatch numbers but their trees are on Gedmatch, I still can't figure that out. Then I read Jim Bartlett's blog. I am on a VERY fixed budget but decided I had to find out what he was writing about. Bingo! All I had to do now was write letters to these people and tell them we match somewhere. Like everything when it comes to genealogy, I just blunder my way around. Where did you do your autosomal test? If it's on ancestry you can exploit their program with a Mirror Tree. There is a fabulous FB group, DNA Detectives. They have great mentors. In their files at the top of the page are some very good resources. In fact, just for your comment I will post the page I private message adoptees. That way it will be out there for everyone to see. Thanks for your comment.

  3. On the left side of your GEDmatch home page is wealth of info about atDNA and using various parts of GEDmatch. Every new GEDmatch user should read through the links in the "Learn More" box. Also there are two levels for using GEDmatch: 1 is just looking at all the Matches (closest ones at the top of the list) and emailing then and sharing info and trying to determine Common Ancestor(s) - this is just basic genealogy; 2 is understanding how helpful close relatives are by finding Matches who also match close cousins, and learning about Triangulation and how that groups Matches. We always need to be #1 genenealogists; and add in #2 DNA as we learn and understand it.