GEDmatch

 
Note: GEDmatch has two interfaces:  "New" and "Classic". It does not matter which one you use. They both have the same functionality. They just look a bit different. The documentation below is for the "Classic" interface.
 
At GEDmatch, you need to pay for Tier 1 services to get access to a report to display your match data. Tier 1 services currently cost $10 to $15 a month with a minimum one-month signup.
 
With Tier 1 services enabled, click on Tier 1 ->  Segment Search. Enter your Kit Number. All the defaults should be okay. You will want to increase the number of closest matches from 1000 to 10000 to get as many of your segment matches as can. Then press the Submit button. It could take anywhere from a few minutes to an hour for the report to run, depending on the server load at GEDmatch at the time.
 
 
Once the report completes, you will get something looking like this:
 
 
Click on the "HERE" to download the segment match file, named:  csvsegmatch_.csv
where:
   .csv indicates this is a comma delimited file which can be read by Excel and other programs.
 
The file always downloads as csvsegmatch_.csv, so if you download the file for a different person, it may overwrite the earlier download. So you should rename the file. DMT uses the "csvsegmatch" text at the beginning of the filename to identify GEDmatch segment match files, so don't change that. I like to put in the person's name and GEDmatch ID number between the "csvsegmatch_" and the ".csv", e.g.:
   csvsegmatch_Louis_Kessler_A123456.csv
 
The output files that DMT creates will include whatever you added after the “csvsegmatch” as part of their filename.
 
When loaded into Excel, the file has the segment matches, as well some additional information not used by DMT:
 
 
Column A (PrimaryKit) is the kit number of the tester, which defines the tester uniquely
Column B (MatchedKit) is the kit number of the person matching, which defines the match uniquely
Column C (chr), D (B37start) and E (B37end) is the chromosome number with the start and end locations of the matching segment on that chromosome.
Columns F (segment cM) and G (SNPs) is the distance in Centimorgans (cM) and number of SNPs for the matching segment.
Column H is the name of the person matching.
Columns I and J are the sex and email of the person matching, which are not used by DMT.
 
Note:  In November 2020, GEDmatch changed the format of their csvsegmatch file and it no longer includes the name of the primary kit owner.  DMT now warns you about this in the log file with the message:
** Person A's name is not available in Person A's segment match file.  DMT will look for it when other match files are processed.
Then in that same run, DMT waits until it processes a File B that contains Person A, and will then inform you in the log file with the message:  "File B contains Person A's name: nnnnnnn"
 
 
The GEDmatch Segment Search screenshot above the statement: "To conserve system resources, matches closer than 2100 cM will not be shown."  This is unfortunate. Your match file from GEDmatch will not include parents, children, siblings, and it's possible that a few of your aunts, uncles, nephews, nieces, grandparents, grandchildren or half siblings could be left out of it.
 
For every segment match file you download, you should run the "GEDmatch One-to-many Comparison Result" to see who you have as matches above 2100 cM:
 
 
The report will be sorted by highest Total cM.  Look for any people with more than 2100 Total cM. My report above doesn't have any. But let's say the first two were over 2100.
 
For each person over the 2100, You'll need to run two reports:
1. One-to-One Autosomal DNA Comparison, and
2. One-to-One X-DNA Comparison
 
Enter the Kit number of the tester as Kit Number 1, and the Kit Number of the person the tester matches as Kit Number 2.
Leave the default values for everything else.
 
The resulting report should look something like this:
 
 
Unfortunately GEDmatch does not have a link to let you download the output from these programs. So there is a button in DMT to let you save the data:
 
 
Run each of the two GEDmatch reports for every person over 2100 cM.  After each run, use your web browser to select everything from the GEDmatch page and copy it to the clipboard. Depending on your web browser, you can do this one of 3 ways:
  • From the menu:  Edit->Select all,
  • With your mouse right-click and pick "Select all", or
  • With the keyboard type Ctrl+A (i.e. while holding down the Ctrl key, type "A").
     
Then copy the selection to the clipboard one of these 3 ways:
  • From the menu:  Edit->Copy,
  • With your mouse right-click and pick "Copy", or
  • With the keyboard type Ctrl+C (i.e. while holding down the Ctrl key, type "C").
 
Then go to DMT and click on the "Save GEDmatch 1-1" button. If the One-to-one data has been properly copied to the clipboard, you should see the following dialog so that you can save that data as a file:
 
 
DMT will assign the filename for you as:  One-to-one_aaaaaa_bbbbbb_ss.csv 
where:
   aaaaaa is the kit number of the first kit in the One-to-one
   bbbbbb is the kit number of the second kit in the One-to-one
   _ss indicates whether this was the Autosomal comparison (at) or if it was the X-DNA comparison (X)
   .csv indicates this is a comma delimited file which can be read by Excel and other programs.
 
The best place to save this file is to same folder where your segment match file for person with kit aaaaaa is. 
 
You don't have to download the file if the reverse file for bbbbbb as the first kit and aaaaaa as the second kit is already in the folder. For person with kit aaaaaa, DMT will first include all the One-to-one's with aaaaaa in the first position, and then will add any others with aaaaaa in the second position.  It will use the first one it finds.
 
You also don't have to download the X file if you have no X matches with the person.
 
If the clipboard does not contain One-to-one data, then you'll get the following message. If you get this message, try the copy and paste again:
 
DMT will also look for any and all GEDmatch one-to-one files that are in:
  • The folder containing File A
  • If "File B" is selected, then the folder containing File B
  • if "Folder B' is selected, then Folder B and if "include subfolders" is selected, then additionally all subfolders of Folder B.
 
You can use a One-to-one file to add any match whether they share more than 2100 cM or not.
 
If the person is already in the segment match file, they will not be included a second time.
 
File B segment match files will only include the One-to-one file if the person is in File A or was added to File A by a One-to-one file.
 
The log file created for the run will indicate which One-to-one files were included with each segment match file.