Tag Archive | GEDmatch

Tool to find common ancestors at GEDmatch

Jul4

Whenever I get a new good-sized DNA match, I try and figure out how we are related. Ancestry and MyHeritage both have clever tools that search your tree and the trees of other users to come up with the likely relationship. Of course both you and your match have to have a family tree connected to your DNA on those sites for that to work.

My father’s DNA matches with matching ancestors, first run

GEDmatch has just released a tool for its Tier 1 (paid) members that will search for the common ancestor you have with your DNA matches on that site. This capability requires both you and your match to have uploaded a GEDCOM to GEDmatch and associated it with your kit. I just updated my 2015 blog post about using GEDCOMs at GEDmatch which explains much about them, so click here to read it. By the way, a GEDCOM is a text file that is formatted especially for genealogy programs; it lets you move the facts in your tree from one genealogy web site or program to another.

The new tool found nothing on my mother’s side. She was German and half Jewish. There are almost no Germans at GEDmatch and my one known half 2nd cousin on there has no tree uploaded. As to the Jewish side, very few have their trees far enough back to meet mine. I need to get a few of my known 3rd cousins to upload GEDCOMs.

The above listing, partially repeated below,  shows all the common ancestors my first run of this tool found for my Norwegian-American father using the default settings on the form. I have cut off the first 3 columns on the left which have the kit number, match name, and email address for privacy; also that makes the image readable on this page!


Let’s look at the rest of the columns for my Dad’s top match. Clicking the tree icon would take you to the user profile information. The cM shared are listed next; 40.3 is match that can be anything from a 4th to an 8th or even more distant cousin. Then the name of the possible shared ancestor, first in my GEDCOM and then in my match’s GEDCOM; either one can be clicked on to go to that person’s tree entry. The 8G is how many steps down from that ancestor my Dad is. If you click that, you see a descendant list from that ancestor in your tree. Notice that his match is also 8 steps down, so in the same generation. Subtract one to get the cousin level so this is a 7th cousin.
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Important Changes at GEDmatch

Dec17

If you have not logged into GEDmatch recently, please do so and either accept the new terms and conditions or don’t. Unless you are clearly USA based*, your kits will not be visible to your relatives any more unless you accept. I have linked to numerous other blogs at the end of this article to help you make your choice. I recommend reading either the one from Roberta Estes or EU users, the one from Debbie Kennett. Both look carefully at the new terms and conditions which are not very different from before.

Frankly, I was surprised by the panic expressed last week by some in the genetic genealogy world on FaceBook due to the sale of our beloved GEDmatch DNA tools site to a forensic science company. Personally, I hate knee jerk reactions so I did some research into this company, Verogen, as well as communicated extensively with Curtis Rodgers, one of the GEDmatch founders, and Kim Mohr, a spokesperson for Verogen.

To remind you all, GEDmatch is the best place to compare DNA tests done at different companies to each other or just to see the actual chromosome locations shared by two Ancestry testers. While both Family Tree DNA (ftDNA) and MyHeritage accept uploads of tests from other companies so you can compare on those sites, neither has the extensive tools of GEDmatch. FtDNA compares down to very small segments which can be useful in a family project but leads to inaccurate relationship estimates. MyHeritage does not show the X chromosome and neither company shows the fully identical segments (FIRs) that full siblings will have, which can be so helpful (click here).

The DNA Applications menu at GEDmatch

GEDmatch has many useful additional tools, such as “People who match both or 1 of 2 kits ,” an “Are your parents related?” test, the ability to see who matches you on a specific segment, being able to check for full siblings rather than half, and automated triangulation, to name a few of my favorites (click those words to go to that post when I did one or click here for my more general GEDmatch articles). Plus it has GEDCOM comparison utilities. Compare yours to all the ones in the database or to just one other.

GEDmatch became a center of controversy when it was discovered that genetic genealogist Barbara Rae-Venter, working with law enforcement (LE). had solved the Golden State Killer case (click here) using that site. Since that time, there have been more controversies around law enforcement’s use of the site and many overblown scare articles in the press. Personally if my DNA outs a distant cousin who is a murderer or rapist, that’s fine with me. Genetic genealogy techniques are used as a tip; no one is arrested without getting their DNA from discarded materials and seeing if it is a match to the crime scene. I know some people are afraid of the possibility of false arrests, but that just does not happen with these modern techniques. You can, as before, choose to opt out of allowing LE to see your results on GEDmatch when looking for cousin matches to the dna of the perp or the unidentified victim.

In recent months, there have been more problems, news stories and controversies, including a Florida search warrant being granted. One has to feel for the two retired hobbyists who founded GEDmatch to help in their research and ultimately help us all, keeping most of the features free. Clearly getting the site owned and managed by a more professional group would be of great advantage to the users. Curtis spent several months looking for the right partner that would respect the original misson of GEDmatch and yet deal appropriately with LE, the EU, and security issues. He and the programmers, the two Johns, will continue to work on the site as consultants.

So who or what is Verogen? Two years ago this company was spun off from Illumina (the maker of the chips and machines that all the consumer oriented DNA testing companies use to sequence your DNA). It has 50 plus employees and plans to continue growing. Their office is in a small office park near UCSD here in San Diego. Continue reading →

More Clustering Tools!

May7

There are many new ways to make those beautiful cluster diagrams of how your DNA relatives are related to each other. Both MyHeritage and Gedmatch (tier 1) now have clustering tools (Thank you Evert-Jan Blom). These charts give you an easy way to see your family groupings and can help you figure out a new match since each cluster typically represents a common ancestral couple. Click here for my previous posts on clustering which is based on the Leeds method.

My Dads Clusters at Gedmatch GENESIS

The GEDmatch cluster diagram shown above includes the total cM each match shares with you as well as their name and kit number. Click on the “i” in a circle for a pop up box with the user information which includes an email address and whether a GEDmatch tree is linked to this kit. Any of the colored boxes on the graph can be clicked to open a window for a one to one comparison between those two people. Plus you can check the boxes in the select column for any number of matches and then submit them to the multi kit analysis using the orange “Submit to Multi Kit Analysis” button above the name column on the left. To get this clustering tool all you need is a Tier 1 membership and a kit number. It is listed at the bottom of the Tier 1 tools. Personally I like to raise the thresholds to a top 200 and a minimum of 20, but try the defaults first and see what is best for you.

One of the nice things about the cluster output from Genetic Affairs is that it lists all the cluster members in groups below the graph with the number of people in each tree (clickable) and any notes you made on the Ancestry profile. The MyHeritage version also has those cluster lists with your notes and the tree sizes; and of course they are clickable to the match (which may even have a theory of family relativity for you!) and the match’s tree. The down side is that you cannot select the parameters for the clustering yourself, they are preset. Possibly only power users care about that!

Extract from my list of matches in each cluster at MyHeritage

An exciting new feature for those looking for one unknown parent or grandparent is the ability to cluster just your starred Ancestry matches when using the clustering tool at Genetic Affairs.  Click here for my previous post about that tool. There now is a checkbox on the page where you select your parameters for getting a cluster analysis.

Newat Genetic Affairs is the checkbox for only starred matches when starting a cluster analysis

It is a common practice to star (mark as favorites) the matches that seem to be from the family of an unknown parent or grandparent at Ancestry. Usually these are determined by looking at who matches or doesn’t match a close relative like a half sibling or else by eliminating matches from the known side. Sometimes you can use ethnicity. I am currently helping someone where the known side is Jewish and the unknown side is Italian and those are easy to separate.

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Make a combined DNA kit for yourself

Apr7

Have you ever wanted to make a kit combining all your DNA tests at the different companies so as to get the most SNPs for comparisons? Well GEDmatch provides that for paid members. So of course I made one of these superkits for myself! I combined my LivingDNA with my V3 23andme and my current Ancestry kit. Now to investigate what I have gained from this.

The first thing I did was compare this new kit to my recent Ancestry kit. All looked fine. It has the expected small differences, many of which disappeared (including the black lines) when I checked the prevent hard breaks box on the form. The older 23andme kit comparison had more black spots and mismatches.

My next thought about my new superkit was that I might get a better comparison to cousins who tested more recently at 23andme but none of them have uploaded to GENESIS yet. So I checked how my comparison to an Ancestry tester, my second cousin once removed Jeanie, looked. The superkit gets the same result as my recent Ancestry kit. When I compared her to my 23andme kit and my Living DNA kit however, there were small differences.

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Basics: GEDmatch reinvented part 1

Feb11

UPDATE 18-AUG-2019: Since the GEDmatch site and GENESIS are one and the same now I have updated this post to say GEDmatch rather than GENESIS

GEDmatch.com is a free 3rd party site of tools where you can upload your DNA test results and compare them with those from people who have tested at other companies. It is the new version of GEDmatch.com that can compare the data from many more companies than the original. Click here for my previous post written for GEDmatch users moving to GENESIS. Today’s article is to introduce the new version of the GEDMATCH basics to the new tester.

GENESIS Home page for my cousin who has only 2 kits migrated and is not a Tier 1 member

One problem for many users is that this site is not intuitive. GEDMATCH does not hold your hand and does not build your tree for you. You have to learn how to use the tools there to the best advantage for your own research. I have many posts on this blog for GEDmatch, . UPDATE 17 FEB 2019: Click here for the slides from my presentation about the basics of using this site from Saturday Feb 16, 2019, in Carlsbad for the North County DNA Interest Group (DIG).

To get started at GEDMATCH, you have to be registered as a user.  Your login will be your email address with a password you create. Some people prefer to use an email which they have created just for genealogical research. Easy to do at gmail, hotmail, or yahoo, among others and it is a way to create some privacy. Note that GEDmatch is careful to warn you when you register that their site can be used by law enforcement to try to identify violent offenders and victims. Click here to understand how your DNA can out a distant cousin who is a criminal.

Before you can use GEDMATCH to explore your test results, you have to download your DNA data from your testing company. Click here for the help page that GEDmatch provides on how to download your DNA. The file of your test results is quite large (about 700,000 lines of data) and zipped. DO NOT UNZIP it.

To upload your results to GEDMATCH you log in and then click on Generic Uploads (23andme, FTDNA, AncestryDNA, most others) in the right hand column under Upload your DNA files. That takes you to a form to fill out before doing the upload. You have to enter the name your kit was registered under, but you can choose to use a pseudonym to appear on GEDMATCH. Put it in the box for alias on this form. For example, all my cousins are called Kittys#CuzNN where the number sign is 1st, 2nd, or 3rd, and NN is their initials so that I know who they are! You have to change the No to a Yes after “You authorize this data to be made available for comparisons in the GEDmatch public database” if you want your results to be visible to your matches.  If you want to stay private, then leave it as is for now, but change it after it is uploaded to “Research” so you can use all the tools on the site but stay invisible. Once your or your cousin’s file is uploaded, you are assigned a kit id (2 letters plus several digits) which will also always show on your home page when you log in. You need a kit id to use the tools. You can upload multiple tests and manage them all from this one user.

You can make edits to any kit you own by clicking the pencil icon next to it on the left side of your home page. Click here for my presentation slide that shows you that edit screen and where to change the privacy to public or research or private.

It usually takes a day or two to fully process your kit so that you can run the most important tool: the one-to-many. That is the tool that lists your DNA relatives in the GEDmatch database. While you wait you can experiment with the ethnicity tools (called admix here) covered in my Gedmatch basics post and in detail in these slides (click here).

If some cousin, like me, asked you to upload and gave you their kit number, you can do a one to one compare with that kit before your kit is fully ready for the other tools. Click here for the slide that shows the form to make that comparison. There are slides following that one which have some examples. You can use all the defaults when you fill out the form with one exception: you may prefer to check the prevent hard breaks box at the bottom. That is particularly recommended for an X one to one. Personally I prefer to look at the image only comparison first, then I click back and select position only to get the numbers for each segment to put in my master spreadsheet.

Once you see a blue check mark on the line with your kit number on your home page (as in image above), you can run the one to many tool. That looks at all the other kits in the database to find people whose DNA matches yours. The more cMs you share, the closer the match.

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