How to use GEDmatch - Part 1

What is GEDmatch?

GEDmatch.com is a volunteer-run website for people who have already tested their autosomal DNA at DNA testing companies such as AncestryDNA, 23andMe, Family Tree DNA (Family Finder test only), and MyHeritage DNA. 

At GEDmatch you can compare your DNA results with the results of people who tested at other DNA testing companies.

GEDmatch has wonderful tools to enable you to contact your DNA matches, compare family trees, and see matching DNA segments.

Getting Started with GEDmatch

If you don't have an account, go to GEDmatch.com and create one.

To get the most from GEDmatch, you will need to load two things:

• Your raw DNA data from your DNA testing company
• Your family tree

To see how to upload these two items to GEDmatch see Getting started with GEDmatch. 

Now log onto your account, and let's examine how to make matches.

One-to-Many Matches

Click the One-to-many matches link in the Analyze Your Data section.

On the next screen, enter your kit number.  If you administer several kits, you can select the kit number from the drop-down menu.

Click Display Results at the bottom of the screen.

Your list of matches will appear on the next page.  It will look overwhelming at first, but don't give up! Let's look at the table headings.

• Kit number is the number assigned by GEDmatch. Each kit begins with a letter that indicates the testing company. For example: A is for Ancestry DNA; H is for MyHeritage; M is for 23andMe; T is for Family Tree DNA's Family Finder.
• Type is the type of testing chip used by the DNA testing company.
• Use the List column to display a list of people who share DNA with one of your matches.
• Use the Select column to compare two or more kits.
• Sex is for the sex of the person taking the test.
• GED/WikiTree contains a link to your match's family tree. GED indicates that it was uploaded from a GEDCOM file. Wiki is a link to WikiTree.
• The haplogroup columns are not very useful since they are for Mitochondrial DNA and Y-DNA. GEDmatch only compares autosomal DNA. However, if you are searching for your direct paternal or maternal line, this column can indicate if your match is within the same ancestral haplogroup.
• The Autosomal Details column is a column you will use frequently. You will click a blue A link to see a comparison of your DNA to your match's DNA.
• The Autosomal Total cM indicates the total amount of shared DNA between you and your match. It is measured in centiMorgans. Largest cM is the amount of DNA in your largest shared DNA segment.
• Gen is the estimated number of generations to your shared ancestor.  This is only an estimate and will often not be accurate.
• The X-DNA columns are similar to the autosomal DNA columns. Click the X in the Details column if you want to compare shared DNA on your X chromosome. Please note that X-DNA is not the same as mitochondrial DNA. They have very different inheritance patterns. The difference will be shown later in this article.
• The last two columns are very important. They contain the name or alias of your match and the email address. This is especially useful when your DNA company does not provide email addresses.

You can sort your matches by any of these columns. For example, if you want to sort your matches by the size of the largest X-chromosome segment, click one of the blue arrows in the X-DNA largest cM column. 

If you are sending an email to someone and you want to see multiple kits managed by this person, click the blue arrow under the Email column.

Find the common ancestor

Here is a partial list of matches from the One-to-many comparison. The columns for Kit number, name, and email have been removed. 

You want to see if you can find a common ancestor between you and your match.  Often you will find a common ancestral couple from whom you both descend. See if your match has a family tree. Click the link in the GED/WikiTree column.

If there is no link to a family tree, you may wish to contact your match to see if he/she has an online family tree. 

There will not be a GED or Wiki link next to your own kit unless you loaded a family tree. If you haven't, please fix it! See Getting started with GEDmatch.

Comparing family trees

I have contacted one of my matches who did not yet load a family tree to her GEDmatch account. Her name is Debra, and we compared family trees at Ancestry.com. Below is my family tree. 

  
Here is Debra's family tree.

Our common ancestors are Willis Collinsworth and Laura Burleson. Debra probably inherited a lot more DNA than I did from Willis and Laura because they are her great-grandparents, and they are my 3rd-great grandparents.

Comparing DNA

Now we get to the best part of GEDmatch--viewing the DNA you have in common.

Click the A in the Autosomal Details column to compare DNA.

 

When you click the blue A you will be doing a one-to-one comparison. 

The two kit numbers (yours and your match's) will be automatically entered into the entry form. Click Graphics and Positions to view a complete match. Click Submit at the bottom of the form.

You will see the chromosome browser on the next page.  When you click "Graphics and Positions" you see a graphical representation of your chromosomes. 

If there are any matches they will be highlighted with the following colors. The blue Matching segment size will change based on the settings you set in the Comparison Entry Form; 7 centiMorgans is the default size.

You can change the segment sizes in the chromosome browser by entering a different value in these sections:

For example, if you change the Minimum segment cM size from 7 to 10, your key will appear as follows.

Comparing my DNA to Laura's, we see in the chromosome browser that our only common DNA was found on Chromosome 5. 

The blue bar indicates that the segment size is greater than 7 centiMorgans. The yellow tells me that this is a "Half Match" meaning that it came from only one of my parents.  

The Position table above Chromosome 5 tells the exact chromosome position and size of the match.

Since I know the common ancestral couple, I can begin to prove that the segment on chromosome 5 was inherited from either Willis or Laura. 

A DNA match to one person is not enough to prove that this DNA segment was inherited from Willis or Laura.  It could have come from another common ancestor that we have not yet identified. 

I need to find other descendants of Willis and Laura who share the same DNA segment. There are many tools to do this. One great tool is DNA Painter. See the link at the bottom of this article.

We will examine some of the other tools in future articles.

Mitochondrial DNA (mtDNA) and X-chromosome DNA (X-DNA)

As mentioned earlier, the inheritance patterns of mitochondrial DNA and X-DNA are different.  Mitochondrial DNA is found outside the nucleus of the cell.  The X-chromosome is found inside the nucleus of the cell.

Mitochondrial DNA inheritance

Mitochondrial DNA is inherited from your strictly maternal line (your mother's mother's mother . . .). Both males and females inherit their mother's mitochondrial DNA, but only females can pass it to their children. Mitochondrial inheritance is shown below in red.

Inheritance of Y-DNA [blue] and Mitochondrial DNA [red]

X-DNA inheritance for males

Males have one X chromosome and one Y chromosome. 

Below is a fan chart [a version of a family tree] for a male. The man's name would go in the circle at the bottom of this family tree. His father's name would go in the first space on the left directly above the circle. His mother is the first space on the right directly above the circle. 

A man cannot inherit X-DNA from any ancestors on his father's side of the family. The male and female ancestors from whom he could have inherited X-chromosome DNA are highlighted in blue for males and pink for females. Here is the pattern of X chromosome inheritance for a male. 

X-DNA inheritance for males

 X-DNA inheritance for females

A female inherits two X chromosomes--one from the mother and one from the father. In the pedigree chart below, the female's name goes in the pink circle at the bottom. Her ancestors are displayed above. 

Here are the possible ancestors from whom a female could have inherited X-chromosome DNA.

X-DNA inheritance for females

 

My match and I share the common ancestors Willis Collinsworth and Laura Burleson. Here is a fan chart of my ancestors pointing the common ancestral couple. I could have inherited X-DNA from either of them.

Again, we see the same family tree shown in pedigree view.

Here is the family tree for my match, Debra. Compare these ancestors to the above fan chart for X-DNA inheritance for females. Debra also could have inherited X-chromosome DNA from either Willis or Laura.

Comparing X-DNA segments in GEDmatch

In addition to the match on chromosome 5, Debra and I have a match on the X chromosome. Debra's kit is the third kit in the image below. Click the blue X link to see the X-DNA match.

In the X-DNA Comparison Entry Form, click on Graphics and Positions, then click Submit.

Using the default settings I see the following:

In the One-to-many match results, it showed that Debra and I share a total of 72 centiMorgans on the X chromosome. 

Because I used the default settings for the one-to-one comparison, the X chromosome browser is showing the largest segment, but no other segments.

Although the X-DNA Comparison Entry Form allows me to change the default values, it does not state what the default values are. However, they are the same as the defaults for the autosomal DNA comparison.

The default value for SNP count minimum threshold is 500, and the default for Minimum segment cM size is 7. I will see a difference in the results in the chromosome browser if I experiment with the settings:

Here are the new X-DNA chromosome browser results: 

Knowing that Debra and I share segments on the X-chromosome is more evidence that we share Willis Collinsworth and Laura Burleson as our common ancestors.

What's next?

Experiment with your GEDmatch account. 

• See your list of DNA matches by clicking the One-to-many matches link.
• Use the GED/Wiki column to see family trees and find common ancestors. If you don't see a family tree link, contact your match using the email address in the Email column of your match list.
• Try the One-to-one autosomal comparison by using the blue A link.
• Try the One-to-one X-DNA comparison by clicking the blue X link.
  

After that, see the following:

• How to use GEDmatch - Part 2. 

• See how to use your GEDmatch results to create a personal DNA map. You can also create a DNA map for your ancestors. See Using DNA Painter to Reconstruct Ancestral DNA.

 

Getting started with GEDmatch

There are two very important items for using DNA testing for family history. 

• Documented family tree. A documented family tree contains proof of family relationships including copies of birth and marriage records, census records, etc. 
• Documented DNA. Documented DNA includes a chromosome browser to prove family DNA relationships. To learn more about the importance of chromosome browsers and how to use them, please see What is the big deal about a Chromosome Browser?

You may have heard the saying, "Genealogy without documentation is mythology."  I'd like to also say, "DNA without a chromosome browser is mythology."

It would be wonderful if the documented family tree and the chromosome browser were together in one location.  This is not yet available at any of the major DNA testing companies.

Even better, of course, would be the ability to compare your DNA results with the results of people who tested at other DNA companies. Family Tree DNA and My Heritage DNA allow uploads of DNA raw data from other companies, but most people have not yet uploaded their results. So if you haven't done it, please do. You will also want to load your results to GEDmatch.

What is GEDmatch?

The biggest resource for DNA comparisons is a service called GEDmatch. At GEDmatch you can upload your raw DNA data from any testing company and also upload a family tree [but not the family tree documents]. 

GEDmatch offers DNA matching to people who tested at other DNA companies, the ability to see their family tree, chromosome browser, admixture reports, and much more. Large numbers of people from all DNA testing companies are using this service. 

Let's get started with GEDmatch to see how to upload the two most important files.

First, you will download your raw DNA data from your DNA testing company and upload it to GEDmatch. Next, you will download your family tree as a GEDCOM file and upload it to GEDmatch.

HOW TO DOWNLOAD YOUR RAW DNA DATA

Follow the directions below for your testing company. You must leave your file in the original zipped format. 

If you are using a Mac, your file may be automatically unzipped. In Safari, go to Preferences, then General. Uncheck the box at the bottom that says, "Open 'safe' files after downloading." The GEDmatch site shows this image:

Please note that it may take several minutes for your files to download.

Download raw DNA data from Ancestry DNA
 

Log into your Ancestry.com account. Click the DNA tab, then Your DNA Results Summary.

On the upper right of the next screen, click Settings.

Find the Actions section on the right of the screen, and click Download Raw DNA Data.

Enter your Ancestry account password, click next to "I understand . . .", and click Confirm.

You will get an email when your download has finished. 

Open the email:

 
Click Confirm Raw Download.

Your raw DNA data file will be downloaded to your computer and will look something like this:

Download raw DNA data from 23andMe

In your 23andMe account, you may have to click on several screens to complete surveys and raw data opt-ins before your can download your results. Log into your 23andMe account, and click Tools.

Then click Browse Raw Data.

On the next screen you will see a tab for Browse and a tab for Download.  Click Download.
 

 
Scroll down until you see Submit Request.  You will get an email when your file is ready. 

Enter your  23andMe password and click Download raw data.

 
Your file will be downloaded to your computer and will look something like this:

Download Raw DNA data from Family Tree DNA

Log into your Family Tree DNA account, and click the myFTDNA tab at the upper left of your screen. Then click the arrow next to Family Finder.

Select Download Raw Data from the bottom of the list.

Click the arrow next to Build 36 Raw Data Concatenated. This file includes both autosomal DNA and X-chromosome DNA.

Your raw data will be immediately downloaded to your computer.

Download raw DNA data from MyHeritage

MyHeritage has a good tutorial on how to download your results.  It includes images, so I don't need to repeat it here. See How do I download my raw data file from MyHeritage?
 

Upload your raw DNA data to GEDmatch

Go to GEDmatch.com, and create an account if you don't already have one.

After you have created and logged into your account, find the File Uploads section on the right side of the page. Notice that there are two sections: Raw DNA file uploads and Genealogy - Family Trees. You will use both sections to load your DNA and your family tree.

Click Generic Upload FAST.

Fill in the information on the next screen. If you don't want your name to be seen by your matches, you can choose an alias, but it should be similar to your real name.

It is very important to click Yes next to the Please acknowledge section. Otherwise, you won't be able to make matches!

Now go to the bottom of the page to upload your raw DNA data file. Click Browse to find the file you downloaded to your computer [it is usually in your Downloads folder].

Find the file you downloaded from your DNA testing company. DO NOT open the file. Here is an example of a raw data file:

Click the name of the file, then click upload.

Watch as your file is uploaded. After it is fully uploaded you will be able to use a few tools, but it will take about 24 hours before you can use the best tool which is the one-to-many matches.

Adding a Family tree to GEDmatch

Now we get to the second important part--uploading your family tree. Many people build their family trees on either Ancestry or MyHeritage, so I will show how to download from these sites. You will be using something called a GEDCOM file which stands for GEnealogial Data COMmunication. If you have a family tree at another online website, see its Help section to find out how to download your tree. If you use a genealogy software program, you can also create a GEDCOM file from your program. See your software User Guide to see how to create a GEDCOM file.

Downloading your family tree from Ancestry.com

Log into your ancestry account, and click trees.

Select the family tree you want to download. Here I have a tree named "DNA Tree." Then click Tree Settings.

On the next screen find the Manage your tree section on the right side of the page. Click Export Tree.

Your GEDCOM will begin processing.

Once your GEDCOM file is complete, click Download your GEDCOM file.

Your GEDCOM file will look like this:

Downloading your Family Tree from MyHeritage

Log into your MyHeritage account, and click Family Tree.

From the drop-down menu, select Manage Trees.

Across from the name of your tree, click on Export to GEDCOM.

Click Begin the export.

Your GEDCOM file will be generated.

You will receive an email when your file is ready. When you download the file to your computer, it will look like this:

Uploading your family tree to GEDmatch

In your GEDmatch account, go to the File Uploads section, and click GEDCOM genealogy upload.

Name your GEDCOM file, and select the GEDmatch kit where you want to attach this tree. Then go to the bottom section and click Browse. Find your GEDCOM file, and click Upload.

Getting started with GEDmatch

Once your Raw data file has processed you will be able to see a list of matches, be able to find common ancestors by looking at their family trees, compare DNA in a chromosome browser, and more.  Your favorite tool will probably be the 'One-to-many' matches. When you click on the link, you can enter your kit number and search GEDmatch's entire database for people who share DNA with you. You can see the exact matching segments by using the chromosome browser.

In the following image you will see a match list. I have removed many of the columns including the ID number, user name, email address, etc. This image may appear daunting at first, but the important column here is the one that has the blue GED. This column indicates that the person has uploaded a GEDCOM file.  Click the blue link to see the family tree. 

The problem is the large number of people who do not have the blue GED link. In the image above, only two of the people have added a family tree. Without that link, the rest of the people are missing the most important part of GEDmatch--the ability to find common ancestors and to see which DNA segments were inherited from those ancestors.

Getting the most from GEDmatch

Remember that it takes BOTH family trees and DNA results to use DNA for family history. If you have not yet uploaded your raw DNA data AND your family tree, please do it now!! Then start exploring GEDmatch.  It's pretty great.

Next we will use GEDmatch with the the most amazing tool ever to reconstruct your ancestors' DNA. I'm serious!  My father and grandparents died many years ago, and I'm reconstructing their DNA. It's not difficult at all. In fact, it's downright fun. You'll love it. 



Up next: Reconstructing the DNA of our ancestors

and  How to use GEDmatch - Part 1