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September 17, 2020
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How To Use GEDmatch? Is It Safe? | Beginner's Guide

We’re introducing GEDmatch — one of the most popular tools to track down your family members and family history using raw DNA data files.
By
Tomohiro Takano

In this article, we’re introducing GEDmatch, how to upload your DNA data from different DNA testing services into GEDmatch, and explaining each function and how it can maximize your DNA relative match. GEDmatch is one of the most popular tools to track down family members and learn about your family history. Using raw DNA data that you can get from a DNA kit from companies like 23andMe or AncestryDNA, GEDmatch allows you to dive deep into techniques used in genetic genealogy. 

GEDmatch is an extremely powerful tool, however, there is quite a learning curve required to use GEDmatch effectively. Follow along with us to see exactly how you can start using your raw DNA data to research your family history using GEDmatch!

What Is GEDmatch?

GEDmatch.com is a great family finder tool for people who are interested in finding your relatives for FREE. The website offers a suite of professional-grade genealogy research tools that are not for the faint-of-heart!

GEDmatch got its roots when at-home consumer DNA testing services started allowing users to download their raw data. With this genetic data, GEDmatch can run a suite of statistical techniques to help you fully understand your genetic heritage. Previously a non-profit company, the company was recently purchased by Verogen, Inc., a company that focuses on forensic evidence for law enforcement.

The database on the GEDmatch site was one of the first DNA databases that police used to identify criminals - namely the Golden State Killer, who had avoided authorities for 40 years! Verogen clearly valued GEDmatch’s database, which was purchased along with the company. While site policy still allows you to “opt-out” of giving police access to your data, having a database law enforcement can use is clearly now a goal of the company. 

Is GEDmatch Safe?

Though GEDmatch started as free service allowing users to search for family members using their DNA data, the company was purchased by forensic company Verogen. Though the acquisition raised some concerns about user's DNA privacy and the transfer came with some issues, the company still provides users with the option of opting-out of law enforcement searches. The company seems to be abiding by this policy, as there was only one initial issue that resulted from a breach in the system. The issue has been resolved, and no new reports of unwanted law enforcement access have been reported. However, you may want to know more about this incident to put your mind at ease.

In July 2020, the GEDmatch database was breached by hackers. As a result of this incident, the privacy controls on millions of user accounts were overridden. For about 3 hours, this breach allowed law enforcement agencies to see the data of millions of users who had not given their consent. While the site was shut down quickly and the privacy settings were restored, the breach started calls for GEDmatch to be more transparent about their cooperation with law enforcement. For example, companies like 23andMe and Ancestry regularly publish reports that detail the times they were required to disclose user information for legitimate legal reasons. This seems to have been a one-time issue for GEDmatch, though caution is warranted if you do not want law enforcement officials to access your private data without a search warrant.

How To Use GEDmatch

How to Upload Data to GEDmatch

To begin, you must register on GEDmatch.com. 

First, upload your DNA data from DNA testing companies like AncestryDNA. After receiving the test results of your common ancestor, these companies allow you to download your own raw DNA data and upload that elsewhere to access different information, like GEDmatch.


List of companies whose raw data are compatible with GEDmatch (links to respective pages explaining how to download raw DNA data):

AncestryDNA (Ancestry.com)

23andMe

MyHeritage

Family Tree DNA (FTDNA)

LivingDNA

Plus, GEDmatch now claims that “most other” company files are also compatible with their system!

Once you’ve downloaded your raw data file, create a GEDmatch account and upload your data. (We’re writing a step-by-step guide on how to do this in another blog post). Note that it will take a few hours after uploading to see your results. They don’t notify you when it’s ready — but you can check the “Kit ID”, and if it says no kit number registered yet, you need to wait a little longer.


What is a kit number on GEDmatch?

After you upload your raw DNA data for DNA analysis, the company will assign you a kit number. Your kit number is a unique identifier tied directly to your DNA profile on GEDmatch. The kit number will allow you to share your profile with friends, allow them to find you on GEDmatch, and you can search other kit numbers to compare with. 


Kit numbers have a standardized format, which also allows you to see where certain sources of data come from. This is useful if you are trying to track down relatives, as you will get the best results if you submit a DNA data from the same source because the exact same sites will be tested. This will give you the most accurate results.

DNA Application:

Once you have added the file of your DNA results, you are ready to begin exploring! Start on the right-hand side of the page, under “DNA Applications”. This is where all of the free tools reside on GEDmatch. Simply click on each of the tools to get started. Remember: you will need your kit number for most applications.


GEDmatch is commonly used by professional genetic genealogists for genealogy research. The core features include:

  1. One-To-Many DNA Comparison Result: Helps you compare your genetic profile to users in the GEDmatch database. Emails are provided so you can quickly contact them if you get a hit. This is a simple and great resource for telling if you are related to anyone in the GEDmatch database. 
  2. One-to-One Autosomal DNA Comparison: This helps you narrow down the comparison with one specific relative member. Use this to confirm how much DNA data you actually share with that person before you reach out.
  3. Admixture (heritage): This is a well-known analysis for identifying your ethnic roots. Like AncestryDNA and 23andMe, it shows the proportion of your DNA coming from a particular ethnicity/geography. It’s interesting to compare these results with that of other ancestry tests.


However, there are numerous other tools listed on the GEDmatch homepage that you can use for different purposes (as pictured below). For first-timers, we recommend starting out with the 3 tools listed above (boxed in red in the image below).However, once you get accustomed to the free tools, consider upgrading to the Tier 1 package to get some really incredible tools.

You can find each tool on the menu bar above.


GEDCOM Files

You may have noticed that GEDmatch also allows you to upload GEDCOM files, which store information about family trees. Using a GEDCOM file from Ancestry, MyHeritage, or any other family tree software, you can compare your GEDCOM file to all files within the database, allowing you to see exactly how your family tree ties into other people’s family trees. You may even be able to see where you shared a common ancestor!

Tier 1 Tools

Though we won’t get into how to use the advanced tools here, it is worth noting: they are pretty cool. Here is a short description of some of the coolest tools:


Lazarus : Essentially, you can recreate a dead person’s genetic code using samples from their close relatives. While it won’t bring them back to life - it is very helpful for using DNA information from an autosomal DNA test to do deep genetic genealogy research.

Phasing : This tool sorts out your chromosomes by using information from your mother and/or father. This allows you to see exactly which parent gave you that crooked nose!

My Evil Twin : Your parents could have created many versions of you, based on which genes they passed on. This simulation essentially recombines your genetics to estimate what traits your “evil twin” would have carried.


There are many other traits available in Tier 1, allowing you to explore specific segments of your DNA and many other statistical analyses! 

How To Understand The Results

Once your results are ready, you are able to explore a number of features on GEDmatch. Here are the two main tools:

How to Find My DNA Relatives?

1. One-To-Many DNA Comparison Result

When you click “One-To-Many DNA Comparison Result”, you can see a list of contacts like below.

How do you evaluate the results to determine who is a potential relative? Check “Overlap and Total cM” first.

One-To-Many DNA Comparison Result View


“Total cM” is the total length of all substantial DNA segments you share with a DNA match. “Overlap” is the total number of overlapping SNPs that you share with your match. SNPs are “single nucleotide polymorphisms.” You can think of them simply as DNA letters important in determining your unique genetic profile. Therefore, the larger the number of centimorgans you share with another user, the more closely you are related.


The table* below summarizes the total cM expected from different degrees of relations within the family. For example, if your parents’ data is on GEDmatch, they should show up as a match with over 3000 cM shared. If you do it with great-grandparents, it would be around 464-1486cM. Or 46-515cm with a 2nd cousin.


However, GEDmatch also gives you the ability to change and modify this search. You can learn more about how your “match thresholds” can change your results on the ISOGG Wiki.

Degree of family relation implied from “Total cM”

*If you want further details, DNApainter’s comprehensive chart of cM calculator does a good job of explaining this. Note that DNA data files and their coverage of the genome differ across companies, so results may inevitably not be 100% accurate.

Cited from DNA painter under CC4.0 license

In conclusion, by checking “Overlap” and “Total cM”, you may find people who share a significant amount of DNA with you — people who potentially are your newfound relatives!

2. One-To-One Autosomal DNA Comparison

Once you find someone who shares a good chunk of DNA data with you, you can start digging into the details of your DNA relationship with them. The image below is from the One-To-One DNA Comparison Result: it gives you a visual representation of which segments of your DNA you share with that person (chromosome browser). What you want to see is how many blue chunks do you have.

Settings to generate your One-to-One DNA Comparison Results

Blue matching segments have significantly common DNA data between you and your match

This one-on-one matching can really help you narrow down who you are related to and how much DNA you share with that person. You can also start to track which segments of DNA you share with different people - little puzzle pieces in the story of how you came to be.


What Else Can We Do With GEDmatch?

One-To-Many DNA Comparison Result and One-To-One DNA Comparison Result are awesome tools to start with. Besides those, here’s our recommendation for what else to try.

Try out Admixture / Oracle with Population Search. 

This helps you learn what genetic ethnicity you have based on publicly available genealogy databases such as MDLP, Eurogenes, Dodecad, etc.


Here is a summary of the recommended databases to use based on your ethnicity:

MDLP — European, American

Eurogenes — European, American

Dodecad — Eurasians, Asians, Africans

HarappaWorld — South Asian

Ethiohelix — African

puntDNAL — (Unknown)

GedrosiaDNA — Eurasian (Indian and Asian)


Heritage view on GEDmatch

Are Your Parents Related?

This “fun” tool allows you to see if your family is prone to inbreeding. You would be surprised - it is more common than people think, though the relationship is usually very distant. This tool essentially compares each “phase” (maternal or paternal portion) of your DNA to see if they are related to each other. 

X-DNA Comparison

Using FamilyTreeDNA X-DNA data, you can compare your X-DNA directly to other users that have uploaded their data.


One to One X-DNA Comparison is a unique feature that enables you to do the same comparison as "One-To-One DNA Comparison", specifically for your X Chromosome. The main One to One comparison tool analyzes autosomal DNA, which is your numbered chromosomes commonly used by ancestry DNA companies. Y-DNA can trace your paternal line (father's side), X-DNA does the same for your mother's side maternal line.


The One to Many X-DNA comparison allows you to compare to all the users in the database at once and see if you share the same haplogroup and what percentage of the X-DNA you share. For males, X-DNA is very telling of their maternal DNA ancestry (similar to mtDNA). 


You can learn more about how to use this tool on this post as well! 

"How to Understand Gedmatch X One-to-One Results"

Conclusion

Was this helpful? If you have any additional questions about GEDmatch, feel free to leave a comment below or reach out to us at info@genomelink.io. We’d love to hear about your experiences with DNA tests and websites!


This article was written by the Genomelink team. Our mission is to help people learn and do more with their DNA data. Genomelink is a DNA data analysis platform where you can discover stuff about yourself from your DNA besides ancestry. Our 170+ genetic traits includes food & nutrition, health, general wellness, psychological traits, and much more!



Got 23andMe, AncestryDNA, or MyHeritage results back? Upload your raw DNA data to access 25+ free traits and 7 Ancient Ancestry reports
Tomohiro Takano
Tomohiro Takano
Co-Founder and CEO