Great DNA utility website
NOTE: This blog’s recommendation of GEDmatch has been withdrawn due to privacy issues. See “Withdrawing a recommendation,” The Legal Genealogist (https://www.legalgenealogist.com/blog : posted 15 May 2019).
[Note: There’s an Updated look at GedMatch published in 2017.]
It occasionally surprises The Legal Genealogist to realize that not everyone is ready, willing and able to test with every DNA company on the planet, or at least in the United States. Just because doing a full round of tests with Family Tree DNA, 23andMe, AncestryDNA and others will set you back somewhere in the neighborhood of a grand or more is no reason not to let loose your inner DNA geek, is it?
Oh. Yeah. Right.
There is that little problem of the mortgage and the kids’ school clothes and that doctor bill and…
Sigh… Don’t you just hate it when real life interferes with what you want to do?
So to fill in some of the gaps, at least for autosomal DNA tests, let me introduce you to a wonderful website: GEDmatch.com, with tools for genetic genealogy research that carry a whopping big price tag of exactly zero. That’s not a typo. The site is free, though donations are gratefully accepted and anybody who uses the site really should kick in — it isn’t cheap to provide the kind of computing power Gedmatch provides.
The brainchild of Curtis Rogers and John Olson (a distant DNA cousin of mine), Gedmatch offers a range of utilities that make it a little easier to extract every bit of potentially useful information out of your autosomal test results. Autosomal DNA testing, remember, is the kind that works across gender lines so you don’t have to find a direct male line from father to son to son (YDNA or Y-DNA1) or a direct female line from mother to daughter to daughter (mitochondrial DNA or mtDNA2). It particularly helps you identify cousins with whom you can share research.3
To use the site to full advantage, you need to download your raw autosomal DNA test results and match lists from your testing company and then upload them to Gedmatch. Both Family Tree DNA and 23andMe make raw data available — AncestryDNA does not — and directions for downloading are on the Gedmatch site. Gedmatch works with the raw results from deCODEme as well. And you can upload a GEDCOM with your family tree to see if you can identify common lines, using technology to help with traditional paper-trail genealogy too.
Although you do have to provide your email address and the exact name you used with your testing company, you don’t have to use your name publicly. You can be John’s Mom, or CountryCuzzin, if you prefer. You don’t have to make any of your information public if you’d rather not, although the utility of the website is limited if you don’t.
Once you’ve uploaded all the files — and there’s more than one to upload — you’re ready to start playing with the utilities.
First, you can compare your results with the results of all other Gedmatch users who’ve made their results public — no matter what company they’ve tested with:
The results can be sorted by the total amount of DNA you have in common with others, measured in units called centimorgans or cM,4 by the longest segment you share, by the number of generations you’re likely distant from your matches and more. Email addresses of your matches may be listed, but can’t be copied-and-pasted to protect them from harvesting by spammers.
You can choose to see information about selected matches in a chromosome browser. Here’s what my results look like against my two uncles and my aunt on Chromosome 1:
And there are several matrix displays available that will display your selected matches not only as they match you but as they match each other, including a very useful option for displaying estimated distance to the most recent common ancestor.
There’s a genetic distance calculator, a relationship calculator, the ability to triangulate on match results to see how you and your match relate to others, a tool for checking to see if your parents are related to each other, and more.
One of my favorite tools is a quick and easy tool labeled “People who match one person, but not the other …and people who match the same 2 people.” I use it to see others that I have in common with a match, and it quickly produces a chart showing information as to how each of us compares to each common match. The chart does have email addresses, deleted here in this example showing matches I share with an uncle.
There’s more than enough here to satisfy your inner DNA geek. You can phase data — if you and one or both of your parents have tested, this utility will help identify what portions of your DNA came from which parent.
And there are six different options for displaying admixture (ethnicity or deep ancestry) data — and each of the six has options galore. Here’s my admixture under just one of those options:
If that’s not enough, you can even get your very own personal chromosome painting:
For anybody interested in learning more about DNA, or even just playing around with results, this is one cool set of utilities. Kudos to Gedmatch, a DNA geek’s dream site!
- ISOGG Wiki (http://www.isogg.org/wiki), “Y chromosome DNA test,” rev. 23 Jul 2011. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Mitochondrial DNA,” rev. 30 Jul 2010. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Autosomal DNA,” rev. 8 Feb 2012. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Centimorgan,” rev. 24 Jul 2010. ↩