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Gedmatch Frequently Asked Questions

Have you heard of Gedmatch?  Are you wondering what you can learn from it, what it can do for you, and how to use it?  In this post, you’ll find the most common Gedmatch frequently asked questions.

What is Gedmatch?

Gedmatch is a free website where you can upload your DNA and have access to many different DNA analysis tools, as well as DNA matches, and genealogy records like family trees.  The advantage of using Gedmatch is that they accept uploads from several different testing companies. 

This gives you access to more DNA matches, and can possibly help you learn more about your family’s history, since not everyone will have tested with the company that you chose.

Learn more about Gedmatch

Where does Gedmatch get DNA?

Gedmatch does not have access to DNA or DNA samples. Instead, Gedmatch users upload specially formatted files to the site containing DNA data obtained from their DNA testing company.

Is Gedmatch Safe?

Yes, Gedmatch is a very secure website and your personal data is protected.  If you would like to make sure that you remain completely anonymous to people whose DNA might match yours, you can create a generic e-mail address that doesn’t include your name, and use an alias during your DNA upload. 

Additionally, if you upload a family tree, this information is generally searchable by either your e-mail address or your DNA kit #, so you should make sure that the personal details of living people are not accessible.

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How to upload DNA to Gedmatch

It is a fairly easy process to get your DNA uploaded to Gedmatch.  The first step would be to download your DNA from your testing company’s website.  Then, create your Gedmatch account and complete your upload.

How long does Gedmatch take?

You’ve done your upload, and you might be wondering if this is going to take as long as it did when you first did your DNA test with your testing company?  I have excellent news for you: no. 

You will not have to wait very long at all to start using the tools on Gedmatch and get your results back.  In fact, you can use most of the tools within 30 minutes of beginning the process. 

The “One-to-Many” tool, which compares your DNA to all of the other kits on the site, is usually ready to use within a few hours, but can take a day or two at the longest.

Which tools on Gedmatch are most helpful for beginners?

If you are brand-new to Gedmatch and consider yourself a beginner in genetic genealogy, I would recommend acquainting yourself with the following two tools:

These tools are the most useful for users who are just starting out, and once you get acquainted with understanding these results, the rest of the tools will be easier to work with.

Understanding Gedmatch Results

There are several different tools on Gedmatch.  The Gedmatch software will compare your DNA to the hundreds of thousands of other DNA kits on the site, and report to you the top few thousand matches. 

You will have plenty to do once you get your results, since you might find new close matches and family trees of other users that might reveal important information about your family tree.

Below are links to posts about the two most popular, and most useful, tools available on the site:

Are Gedmatch results accurate?

Gedmatch results are very accurate. You should find that your results on the site are similar to results obtained on other sites. You can trust your Gedmatch results.

With this said, you might find very minor discrepancies between the location of DNA segments you share with your matches. The minor difference shouldn’t make a big difference and should only be noticeable with your more distant matches.

How to figure out how your Gedmatch DNA matches are related?

Discovering how our Gedmatch matches are related can be challenging, primarily because many times the only information we have about our matches is their e-mail address. Sometimes, we might have our match’s full name.

While I really do wish more people would upload their family tree to the site (more on this below), a name and an e-mail address is often enough to learn the identity of our match and begin the work of discovering our genealogical connection.

I wrote an entire post on this topic: “How to figure out how your Gedmatch match is related to you.”

What does estimated number of generations to MRCA

MRCA stands for “most recent common ancestor“. Knowing who our MRCA is helps us calculate our exact genealogical relationship to our relatives. For example, the MRCA for two siblings is at least one parent. The MRCA for second cousins is a great-grandparent.

Gedmatch uses the amount of shared DNA between you and your matches to estimate the number of generations between you and your MRCA. Generally speaking, the larger amount of shared DNA, the more recent the MRCA, and the fewer number of generations to the MRCA.

When it comes to more distant cousins, the estimated number of generations to MRCA should be taken as a literal estimate. There are limits to using the amount of shared DNA to predict an exact relationship, and it can usually only help us narrow down how we might be related.

You can read more about using shared DNA to predict how you might be related to a match in my post, “Shared Centimorgans for Beginners“.

How to get more people to upload to Gedmatch?

I have found that adding a profile picture to my DNA results on the different sites where I’ve tested saying “Gedmatch kit #….” (and of course, adding my kit#) is a great way to get the attention of my DNA matches. I’ve had DNA matches ask me what that means, which gives me the chance to explain the benefits of Gedmatch.

Additionally, I generally try to mention my Gedmatch kit # in messages that I send to relatives on the testing sites. It’s less abrasive than “Please upload to Gedmatch”, but it achieves the same result. They become curious about it and end up doing it anyway.

This is especially helpful for sites like Ancestry DNA where we don’t have access to a chromosome browser. If our Ancestry DNA matches upload to Gedmatch, we can access detailed segment data.

Is there a way to upload a family tree to Gedmatch?

Oh yes! I’m so glad that you are wondering about this question. In fact, I wish more people would upload their family trees to Gedmatch because it would make figuring out our connections much easier and make the information that we learn from the site more useful.

Gedmatch accepts family tree uploads in the form of a “Gedcom” file. You can download your family tree from Ancestry or many other sites (or software programs) and follow the instructions on the Gedmatch Gedcom upload page.

You can access the page to upload your Gedcom from your main Gedmatch home screen, as shown in the image below:


We can make Gedmatch more useful for everyone by uploading our Gedcoms.

Total cMs on Gedmatch

It’s looks like some crazy notation, but really cM is just an abbreviation.  It stands for “centimorgans”, which is the unit of measurement that geneticists use to describe the length of DNA segments. 

When you see “Total cMs” on Gedmatch, it is telling you the total amount of DNA that you and a match share with each other.  Generally speaking, the more DNA you share with someone, the closer the relationship.

Should you lower the default thresholds on the DNA comparison tools?

I see a lot of Gedmatch users (and users of the classic Gedmatch site) running One-to-One comparisons with thresholds lower than the default 7 cM legnth.

So, is it good or bad to lower the threshold?

When people are just getting started understanding Gedmatch results, lowering the threshold below the default level on any of the settings can cause a lot of unnecessary confusion.

For example, almost all DNA segments lower than 5 cMs in length are likely to be coincidentally identical segments (IBS), and not DNA segments that two people inherited from a common ancestor. If you compare two kits on the site but have the threshold set to 5, 3, or even 1cM, and spot a match, you are almost definitely going to find yourself searching for a common ancestor who doesn’t exist.

Does Gedmatch give you ethnicty estimates?

This is one of the most popular reasons that people like to upload their DNA to Gedmatch.  There are wonderful researchers out there who work completely independently of the DNA testing companies, and have created DNA projects to provide ethnicity estimates to Gedmatch users. 

It’s quite amazing what you can learn.  They are called Admixture calculators (admixture means “mixing”, and is basically like a report of the mixture of ethnicities that you have).  Each project generally has a focus on a particular region of the world, and some can help you find ethnicities that you might not have located otherwise.

Gedmatch: Native American

Since one of the most popular reasons for using Gedmatch is the ethnicity estimates you can have access to, it makes a lot of sense that one of the most popular ethnicities people are researching is the Native American ethnicity.  Many people have grown up believing that they have Native American ancestry

Does Gedmatch have a Neanderthal calculator?

To my knowledge, there is not currently a calculator on the site that will tell you how much Neanderthal DNA you have (but you can find one here).  With that said, there is something pretty cool that you can do on Gedmatch. 

You can compare your DNA directly with some of the most famous DNA samples out there.  This is even better than a Neanderthall calculator, in my opinion.

Some of the most interesting DNA samples you can compare your DNA to?  Use the Ancient Genomes tool to run your DNA against all of the ancient kits, and then use the One-to-One tool to see how much DNA you share with these samples from people who lived many thousands of years ago. 

You can get their kit numbers from the Ancient Genomes tool results page.

Other sites like Gedmatch

Gedmatch is a fairly one of a kind site, and as of 2018, there is no comparable site that offers the magnitude of access to people who have tested with other companies, as well as the advanced tools to analyze your DNA. 

There is a relatively new site called Geneplaza, which allows you to upload your DNA from various testing companies, but access to the tools is not free, and there is no evidence that they provide information that would be useful for finding relatives or family tree researching.  Additionally, I have no experience with this site, but it’s worth watching to see how it develops.

If you want to make sure that you have uploaded your DNA to all of the available sites, read this post about free places to upload your DNA.

Conclusion

I hope that you learned a bit about Gedmatch and that your most pressing questions have been answered.  If you have any additional questions or comments, please feel free to leave a message in the comments below – I might add your question to the article.

If you have a question about Gedmatch that you don’t see answered here, post it in the comments and I will add an answer to this article.

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