Recently, I received an e-mail from Louis Kessler, a Microsoft platform developer and genetic genealogist who has created a new tool, the Double Match Triangulator:
Double Match Triangulator (DMT) uses two FamilyTreeDNA Chromosome Browser Results files from two different people and combines them in an Excel file to produce a map of all the Double Matches and Triangulated segments between the two people and all third people. It provides a different way of looking at matching segments than the Chromosome Browser and helps identify Triangulation groups.
The program runs on Windows, is free for everyone, includes a short but comprehensive help file, and is available at: www.beholdgenealogy.com/dmt
Please note that this tool is only for Family Tree DNA chromosome browser download files and only runs on a PC. There is no MAC version.
I’m already providing this functionality for the people whose kits I manage and have access to their match list, simply by utilizing a regular spreadsheet. In fact, I combine multiple people in a single spreadsheet to see who matches whom on the same segments. I’ll be demonstrating this in a future blog article.
However, I also realize that not everyone wants to do that manually, so this is a great tool for those who don’t, and it does the math between two people so you don’t have to. The only down side is that it only compares two match files at a time, but given Louis’s format, I don’t really know how he would incorporate more than two files in one comparison file. Besides, I’m not about to look a gift horse in the mouth and I think the DMT tool that Louis has provided is a great service to the genetic genealogy community.
Installation and Instructions
First, let me tell you that you must install this program on your PC. Now also let me say that I’m EXTREMELY leery of installing anything on my PC, especially from a relatively unknown source. However, I could tell from reading the documentation and information that Louis was indeed a genetic genealogist, and I decided the potential risk was worth the potential reward, so I did the install which went very quickly and easily. Besides that, curiosity got the best of me. Yes, I’m apparently part cat, although that has never shown on any DNA test:)
Secondly, let me also say that BECAUSE this program is installed on your own system, and does NOT require you to upload match information into a public location, I’m OK with this. I would have serious ethical reservations if this program were offered on a public site where you uploaded matches to a public location, because your matches have not given permission for that to happen and it’s outside of Family Tree DNA where your matches expect their information to remain. However, since you’re only downloading to your own PC, for kits you manage or who have already given you access, I’m fine with this.
Third, don’t even think of trying to do this without utilizing the help file. I have dual monitors, so I opened the help file on one screen and the program itself on the other screen. The help file contains all of the instructions and column definitions, and you can’t run the program or make sense of the results without this information.
Below is the program screen where you select the two chromosome browser files that you have downloaded from Family Tree DNA to compare. Of course, these must be from kits that you manage or have access to in order to download the chromosome browser matches. Otherwise, you can ask your matches to e-mail you their match file.
The Help button that holds instructions is at the right side below the option boxes, just above the line between grey and white.
The Help screen looks like this and is where you will find all instructions for how to select files, run the program and interpret the results.
Scroll down to the bottom of this main help screen to see the various page selections under the title “The contents of Double Match Triangulator.” You will need to click on each one and read what Louis has written.
The contents of Double Match Triangulator
After following Louis’s installation instructions, I downloaded three chromosome browser files that I manage and am familiar with so that I can determine if the program is functioning as expected.
I selected my cousin Cheryl, cousin Bill Lentz and cousin Rex Miller. All three of these individuals descend from the same lineage and they do match. I already know they have triangulated matches – although the common ancestor of their common matches is not always identified.
I would suggest creating a folder called something like “DMT Experiment” and copy the chromosome browser files you wish to use to that location. Your DMT results file will be in the same location.
After clicking “Run,” the program did not automatically pop up the completed match file, so I sat and waited before thinking to check the folder where I had put the files to use.
Two files were generated, Cheryl to Bill Lentz and Cheryl to Rex Miller. I’m going to use the Cheryl to Bill file for purposes of demonstration simply because it’s smaller.
On the first (default) spreadsheet tab, labeled Map, we see the details of the Person A, Cheryl, matching to person B, Bill, with their common segment matches to a third person listed in the third column, Name-C. The next columns are documented in the Help file, but the column you are most interested in is the Status column which shows the “Full Triangulation” cells highlighted in green. These are the people where person A (Cheryl) matches person B (Bill) who both match person C, on the same segment(s).
While this matching “per segment” information is useful and interesting, Louis fortunately added a second tab, called “People” which shows one row per triangulated person. On the above spreadsheet, an individual match can be listed many times, for as many segments as qualify to be matching or triangulated. For example, you can see above that Donald is listed 3 times in the first few rows of this spreadsheet.
The People page, on the other hand, provides a summary with one line per matching person. So, on the People page, Donald will only appear one time.
The People tab provides a significant amount of information that you’ll need to refer to the instructions to decipher.
However, the most important columns are the first six which show you the names of the two people whose matches are being compared, their common matches (Name-C) and summary information about those matches. Louis’s program did not color code these. I did, for purposes of discussion.
In this case, the first match is between Cheryl F and Bill Lentz to Donald, who is Cheryl’s brother. They all three match on a total of 9 segments for a total of 47.02 cM. That’s significant.
The next two individuals, jerdon and james, also colored green, match on a significant size segment and jerdon triangulates on two separate segments.
These would both be considered strong triangulated matches.
The individual colored yellow is still a relatively strong triangulated match, especially in light of the triangulation, and in particular if the common ancestor is known.
Generally, when matching alone, meaning NOT triangulating, I would dismiss the smaller red segments as probably irrelevant. However, in light of the triangulation, and common known ancestors, I am not nearly so quick to dismiss these. I talked about small segment guidelines meaning how to and how not to utilize small segments in this article.
Among these small segment matches are known cousin Rex Miller, known cousin Roland, mother and me. I would not discard these, but I also would never “call” any relationship on one small segment alone. The good news is that when matching to others, on my DNA Master Spreadsheet, some smaller segments do form triangulation clusters. There is safety in numbers, whether utilizing smaller or larger segments. Of course, larger segments are always safest because they are less likely to be identical by population (or chance) instead of identical by descent. You can review the concepts of identical by descent, chance and population in this article.
Louis has included one more feature. The last three rows are people who match two of three, but not all three people. While these people don’t all match each other on the same segment, they do match a pair and a third person from this same line might well match those two. In other words, in the bottom row, Betty Jean matches Cheryl and Bill, both, but Cheryl and Bill do not match each other on the same segment where Betty matches each of them. More research is needed to determine whether Betty Jean is from the Lentz or Miller lines, or not. It is, however, a good hint to follow. If you would like to review the concept of match groups versus triangulation groups, you can do so here.
For me, I need to sign in to Family Tree DNA to see who jerdon is. Jerdon is the second highest triangulated match and I don’t know anything about that person. I surely hope they have a tree online, and if not, I’ll be e-mailing them shortly. In the mean time, I’ll be doing ICW and trying to figure out which line jerdon is from by utilizing other available autosomal tools.
Have fun with the DMT tool, and thank you Louis. You can catch up with Louis at his blog where he provides additional explanations for his tool and the underlying concepts.